Which of the following describes allopatric speciation? A population of squirrels is separated by the Grand Canyon. Through time the two subpopulations evolve into two distinct species. Two populations of fruit flies are unable to mate because their reproductive organs do not properly fit together. A tetraploid plant species evolves from a diploid ancestor. Both the tetraploid and diploid species are found in the same habitat. One population breeds in the fall; another population breeds in the spring. A male horse and a female donkey mate , producing a sterile hinny.

A virus's ability to infect an animal cell depends primarily upon the A) host cell's ability to phagocytize viral particles. B) presence of receptor sites on the cell membrane. C) type of viral nucleic acid. D) enzymatic activity of a host cell.

Question 1 of 10 Shoots can easily fall over or be carried away by wind or water. What function of the root system prevents this from happening? A. Anchorage B. Cell division C. Storage D. Transpiration

Fill In the Blank Question The movement of respiratory gases between blood and either alveoli or cells of systemic tissues is $\square $ $\square $ Need help? Review these concept resources.

Which of the following represents a viral family name? A) Herpes B) HIV $-1$ C) Polio Virus D) Retroviridae

Impulses carried to the heart by means of fibers that secrete acetylcholine are __ impulses and cause the heart rate to __ parasympathetic; increase parasympathetic; decrease sympathetic; increase sympathetic; decrease

At rest, if blood pressure decreases, what can our body do to increase blood pressure? all of the above are correct increase sympathetic nervous system vasoconstriction decrease parasympathetic nervous system

The complete set of contraction and relaxation events that constitutes one heartbeat is called a __ $\square $

Which blood vessel type has the lowest blood pressure? arterioles veins Venules capillaries Arteries

In what type of blood vessel is the tunica media the thickest? $\square $

What do the SER and RER have in common? the synthesis of proteins the processing and modification of proteins the presence of ribosomes the synthesis of phospholipids the formation of transport vesicles