Dengue fever is an infectious disease of humans that is caused by a virus. There are four main viral strains, and an individual can never be infected by the same strain twice. However, a second infection can occur by any of the other strains. The severity of the second infection depends on the identity of both the strain that caused the first infection and the strain causing the second infection, as well as the order in which these were acquired.

Required:
How many different levels of severity are possible for an individual acquiring a second infection

Answers

Answer 1

Answer:

12

Explanation:

Suppose the four different strains are P, Q, R, S. Thus, the first infection can be from any of the four strains and it occurs in 4 ways.

Since an individual cannot be infected again with the strain from which he/she is been previously infected;

Then, at the second time;

The possible number of strain to be infected with = 4-1 = 3 ways

Thus; the number of possible different levels of severity can be viewed by forming two lettered word  P, Q, R, and S without repetition which is:

= 4 × 3

 = 12


Related Questions

The definition of a parasitic relationship is what

Answers

Answer:

A parasitic relationship is one in which one organism, the parasite, live off of another organism, the host, harming it.

ii) Glucose is absent in urine yet present in glomerular filtrate​

Answers

Answer:

Glucose will be present in blood plasma and glomerular filtrate, but not present in urine (normally) This is because the glucose is selectively reabsorbed in the proximal convoluted tubule. It is reabsorbed from the filtrate into the blood by active transport (symport with Na+ ions)

Explanation:

Glucose will be present in the blood

That is the table pls help

Answers

Abena is the smallest Elephant. Chipo is the largest Elephant. The increase in shoulder height of Bisa over 15 years is 85 cm.

How do elephants develop and grow?

Early in their second decade of life, elephants become sexually mature. African elephants reach sexual maturity between the ages of 10 and 12, while Asian elephants reach sexual maturity around the age of 14.

How much time does it take an elephant to grow up?

Total Size. Physical and emotional development in elephants takes a very long time. The majority of their size is reached by the age of 15, but they frequently continue to gain weight and develop in size until they are around 20 years old.

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Cell wall hut not cell
,
Robert Hooke discovered
Organelles.​

Answers

Answer:

Explanation:

WHAT IS YOUR QUESTION ??

Robert hooke discovered cell wall but not the cell organelle because the cell organelle is much smaller in size as compared to the cell wall. Explanation: The microscope which was used by the scientist Robert hooke was a simple microscope

period when cell is not engaged in division

Answers

Interphase is the period of cell cycle in which the cell is not engaged in any kind of cell division. This phase is marked as the preparatory phase for the actual cell division.

What is Cell cycle?

The cell cycle is a series of steps during which the chromosomes and other cellular material double to make two copies of the genetic material. The cell then undergoes division to form two daughter cells, each of the daughter cell receiving one copy of the doubled chromosomal material. The cell cycle is complete when each of the daughter cell is surrounded by its own outer membrane.

   

The interphase is the period when the cell is in a non-dividing state of the cell and this phase can be in different stages: the first gap (G1) between the last mitosis (M) and the S-phase (phase of DNA synthesis) and the second gap (G2) phase between the completion of the S-phase and the next mitosis (M).

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All living cell's are composed of?

Answers

All living things are composed of cells

Answer:

All cells are made from the same major classes of organic molecules: nucleic acids, proteins, carbohydrates, and lipids.

Explanation:

All cells are made from the same major classes of organic molecules: nucleic acids, proteins, carbohydrates, and lipids.

4. If the mass of two objects increases and the
distance between them stays the same, what happens to the gravitational force
between the two objects?

A. It decreases.
B. It remains the same.
C. It fluctuates.
D. It increases.

Answers

Answer:

As the mass of either object increases, the force of gravitational attraction between them also increases.

Why is purification of water and nutrient salts so important in studies involving mineral nutrition using hydroponics?​

Answers

Answer:

Hello!!!

Explanation:

Aish hi hona tum?

Q1: what is sleet?

Q2: how big can raindrops get?

Answers

Q1. It is a form of precipitation that consists of ice pellets often mixed with rain or snow. it is usually soft and contains some traces of ice. It can be dangerous to drive with this on the road.

Q2: They can get as big as 4 millimeters. rain drops don't usually get any bigger without seperating into two droplets.

Explanation:

(I hope this helps! Have a great day!)

60 POINTS!!!!!
What would happen if a new predator were introduced to prey with which it has not coevolved?

Answers

Answer:

If a new predator were introduced to prey with which it has not coevolved, it could have a devastating effect on the prey species. The prey species may not have adapted behaviors or physical characteristics to protect themselves from the new predator, making them easy targets for predation. This could lead to a decrease in the prey population and an increase in the predator population, ultimately resulting in the destruction of the prey species. Additionally, the introduction of a new predator could disrupt the balance of the existing food web, which could have a ripple effect on other species in the ecosystem.

Explanation:

Answer: leading cause of extinction is the introduction of predators into an isolated system like an island or a lake

definition for artificial language​

Answers

Answer:

An artificial language is a language that has been created by humans, as opposed to a natural language, which is a language that has evolved naturally over time. Artificial languages are typically constructed to be used as a means of communication between humans, although they can also be used for other purposes, such as computer programming.

Explanation:

Cathleen Crain of LTG Associates, Inc. discovered through her participant observation with the HIV/AIDS outreach worker that:

a. men in the community were not using condoms.
b. women prostitutes never carried condoms.
c. the outreach worker had poor communication skills.
d. the outreach worker had stereotypes of prostitutes.

Answers

Answer:

d. the outreach worker had stereotypes of prostitutes.

Explanation:

Cathleen Crain is a co-founder of the LTG associate Inc. She is an anthropologist and her company has been doing absolutely well in anthropology based research, as a socula scientist, she is also a health research analyst specializing in community health and development. Through her participant observation with the HIV/AIDS outreach worker, she noticed the outreach worker had a stereotypes of prostitute.

Why is herbivores insect is least common?

Answers

Most insects are herbivores in a stage of their life, but most of the time later on they because omnivorous (plant and meat eater) so therefore they don't stay herbivorous for long. Also, most herbivorous insects get eaten quite often.

Anya is a veterinary scientist who works in a lab that is attempting to develop better treatment against snakebites. She is currently setting up an experiment that involves running a current through the venom to see if that will separate the particles inside. In the past, this has not worked, but Anya has high hopes. If you were to read the research paper that Anya writes after the experiment, which would MOST likely be the title?

A.
Exploring Chemicals that Combat Viperine Venom

B.
Results of Shock Therapy on Elapine Venom Samples

C.
Discussing the Quality of Antivenin Serums on the Market

D.
Using Radiation to Dissolve Elapine Venom

Answers

Answer: B

Explanation:

Which of the following science related statements are observations rather than opinions? Select all that apply.

Answers

The most frequent cause of coronary artery disease is the accumulation of fatty plaques in the arteries (atherosclerosis). Poor eating habits, inactivity, obesity, and smoking are risk factors. Choosing a healthy lifestyle can help reduce the risk of atherosclerosis. Thus option C, D is correct.

What are the most common heart disease?

The most prevalent kind of heart disease, coronary heart disease, will claim 382,820 lives in 2020. 20.1 million adults aged 20 and older, or 7.2%, have CAD. Nearly 2 in 10 fatalities from CAD will occur in adults under the age of 65 in 2020.

Therefore, In the US, heart disease is the leading cause of death. Additionally, fewer bees have been visiting my garden lately, indicating that bee populations are declining.

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The given question is incomplete. Complete question is given below:

Which of the following science related statements are observations rather than opinions? Select all that apply.

Whaling should be banned.

Cancer is the worst of all diseases.

Ocean acidity was greater in 2010 than in 2000.

Heart disease is the major cause of death in the United States.

Fewer bees have been in my garden recently, so bee populations must be decreasing.

Human activity can contaminate water resources by introducing excess ____, such as nitrogen and phosphorous found in______ and human waste.

Answers

Answer:

minerals and industrial.

Explanation:

Human activity can contaminate water resources by introducing excess minerals such as nitrogen and phosphorous found in industrial and human waste. The agricultural activities such as applying fertilizer and pesticides pollute the water bodies while on the other hand, human waste which is not properly dispose pollute the environment and water bodies that has adverse effect on the environment and its organisms that are present in it.

Gus drew a diagram to compare marsupial and placental mammals

which label belongs in the area marked Y?

a) have a two-week gestation period

b) young develop inside body

c) sometimes lay eggs

d) are endotherms

please help fast, thank you!

Answers

Answer:

A

Explanation:


HELPP PLSS ASAP
Which of the following is a place where you would expect to find an immovable joint in the body?
A. wrist and hand
B. shoulder
C. ribs and sternum
D. back bone

Answers

Answer:

i think backbone is the correct answer

Answer:

Explanation:

I believe the answer is C) Ribs and sternum

The disadvantage of batch fermentations, as opposed to continuous feed systems, is that

Select one:
a. new substrate must be added to the fermentor continuously for the fermentation to continue.
b. there is a limit to the amount of product formed since all materials are added to the fermentor at the beginning.
c. it is small scale production of a product.
d. the end product is not as pure as the product made by the continuous feed process.

Answers

Answer:

according to me may be option number b

Question 18(Multiple Choice Worth 2 points)
(06.04H MC)
Which of the following occurs during birth?
O Pituitary hormones are released, and the fetal heart begins to beat.
The fetal nervous system becomes activated, and the cervix opening expands.
The fetal nervous system becomes activated, and the fetal heart begins to beat.
O Pituitary hormones are released, and the opening of the cervix expands.

Answers

Answer:

options 2 The fetal nervous system becomes activated, and the cervix opening expands.

3. Based on the data, which beak type was more adapted and which was the least adapted?

4. What would happen if all of the birds flew to a new location and the only food available was beans? Which bird would be most successful? Which bird would be least successful?

5. If you come back to this location (question 4) in 50 years, what would you expect to see? (What type of bird will be the most abundant?)

6. Suppose a drought caused the local extinction of beans, pennies, and paperclips. Using your knowledge of the different beak shapes in your community, and understanding of the steps of natural selection, explain how the change in the environment would affect the populations of bird species.

7. List and briefly explain two other characteristics (other than beak shape) that could help a bird survive if this were a "natural" environment.

1.

2.

8. Using at least three complete sentences, explain how this lab simulation provides support for evolution and the Theory of Natural Selection.​

Answers

The bigger beaks types of bird species were more adapted able to eat the larger and harder seeds so more of them survived.

What are types of beak among birds?

Meat-eater, Fruit-and nut-eater, Seed-eater, and Nectar-feeder beaks are seen among birds differentiated based on the nutrition and food consumed.

What three adaptations do birds have?

Beaks (bills), feet, and plumage, in particular, are three physical traits that show distinct environmental adaptations (feathers). The mechanism of evolution that produces living organisms that are adaptable to their circumstances is natural selection.

What technique backs up the hypothesis of evolution?

Evolution is supported by fossil data. Numerous fossils' geographic details show that two species with a shared origin can evolve differently in various environments. An organism can be thought of as an early form from which later forms descended.

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The Arg genes that encode the enzymes for arginine biosynthesis are located at several positions around the genome of E.coli, and they are regulated coordinately by a transcription regulator encoded by the ArgR gene. The activity of the Arg R protein is modulated by arginine. Upon binding arginine, ArgR alters its conformation, dramatically changing its affinity for the DNA sequences in the promoters of the genes for the arginine biosynthesis. A. Given that ArgR is a repressor protein, would you expect that ArgR would bind more tightly or less tightly to the DNA sequences when arginine is absent?

Answers

Solution :

The Arg genes is used to synthesize the arginine. Arginine is chemical building block. It is very important and is used by our body to make the proteins for our body. When the Arg ID is abundant, the expression for the biosynthetic genes must turned off. And if the ArgR behaves as the gene repressor, then the binding of the arginine increases the infinity for the regulatory sites, and allows it to the bind and then shut off the expression of the genes.

If the ArgR acts as the gene activator, then the binding of the arginine would be predicted to reduce the affinity for the regulatory DNA, and preventing the binding and the shutting off the expression for the Arg genes.

The following shows a food chain in a garden environment.
Sun → grass → grasshopper → bird
Which statement describes the energy transfer in this food chain?

A.The energy from the bird is transferid back to the grasshopper.

B.Only a small amount of the energy the bird receives from the grasshopper is used by the bird.

C.The grass passes all of the energy it receives from the sun to the grasshopper.

D. More energy is transferred from the grass to the grasshopper than from the grasshopper to the
bird.

Answers

The correct answer is D

What process occurs when molecules move from a crowded area to a less crowded area ?


Show/tell me the EVIDENCE

Answers

It’s called diffusion, it’s the random motion of particles from high areas to low areas.

Which of the following is the definition of animal husbandry?

ANSWER: C. keeping, caring for, and at times, breeding animals

A. mating animals to create or maintain specific breeds
B. selecting two animals to mate because of specific traits
C. keeping, caring for, and at times, breeding animals
D. raising fish in open-ocean farms or artificial environments​

Answers

Answer:

animal husbandry refers to keeping,caring and sometimes breeding animals

Answer:  The correct answer is C. keeping, caring for, and at times, breeding animals

Explanation:  This answer has been confirmed correct.


What effect would a series of major volcanic eruptions have on global climate change?

A) the increase in atmospheric particles with increased range globally

B) The blanket effect of Ash would increase temperatures globally

C) atmospheric ash circulation would cause extreme temperature fluctuations and rainfall

D) Ash clouds would reflect the suns energy and decrease temperatures globally

Answers

The effect that a series of major volcanic eruptions would have on global climate change would be Ash clouds would reflect the sun's energy and lower temperatures globally.

What is volcanic winter?

A volcanic winter is the reduction in temperature caused by volcanic ash and sulfuric acid droplets obscuring the sun, usually after a volcanic eruption. Long-term cooling effects are primarily dependent on the ejection of sulfide compounds in aerosol form into the upper atmosphere.

With this information, we can conclude that a major eruption would cause a volcanic winter, with a reduction in temperatures globally.

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This is when a weaker animal copies stronger animals' characteristics to
warn off predators

Answers

Explanation:

Mimicry: When a weaker animal copies stronger animals' characteristics to warn off predators.

Over generations of time, what would you expect a population of organisms that are well adapted to their environment to do?

Increase
Decrease
Become Extinct
Stay the same

Answers

Answer:

Increase.

Explanation:

Because they have to adapt if they don't the will be extinct.

state two types of water​

Answers

Answer:

Mineral water and Distilled water

how do i scientifically defend the theory of evolution

Answers

Answer:

wait wdym defend? like you're in an argument about the theory of evolution and you want to defend your point........?

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