1. the main function of the digestive is to

a. break down large molecules into small molecules and absorb nutrients
b. excrete oxygen and carbon dioxide
c. synthesize minerals and vitamins needed for a healthy body
d. remove waste products from the blood

2. the basic unit of structure and function in the nervous system are

a. neurons
b. axons
c. dendrites
d. neurotransmitters

3. the central nervous system consists of

a. sense organs
b. reflexes
c. brain and spinal cord
d. sensory and motor neurons

Which class of molecules contains the amino group, nh2 (a) sugars (b) water (c) proteins (d) hydrocarbons

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

Examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. polyploidy is creating new species. the two populations are not interbreeding freely. hybrid offspring of the two populations begin to appear. one species will increase into a population size twice as large as the other species.