A factor that is manipulated in an experiment is a dependent variable.

a. True

b. False

Why is it difficult for a person with hiv to fight infections?

Sponges can reproduce a. by the budding of new sponges from the parent. b. by a breakup of the original parent into fragments that each become a new sponge. c. sexually, using the production of sperm and eggs. d. All of the above

Allen and Andrew have the same biological parents. Why do they not resemble either of their parents?

What is the best example of how the nervous system maintains homeostasis A. THe parasympathetic system counteracts the sympathetic system. B. The spinal cord returns the body to homeostasis after the brain reacts. C.

The theory of evolution by natural selection is a good example of how science proceeds because

Describe two factors that cause variations in climate?

A demonstration is performed during a lecture on muscle physiology in which a student is asked to fully extend his right arm with the palm up. Two large textbooks are placed on his palm, one at a time.

How is it that the heartworm is able to multiply in numbers at such a fast rate?

Ground squirrels are found in many areas of the United States. They live in underground burrows and are often attacked by birds of prey, coyotes, and boBCats. Which of the following is a limiting factor for a ground squirrel population?

10. Which of the following is an emerging dis- ease that was unknown 50 years ago? a. malaria b. dengue fever C. Lyme disease d. schistosomiasis