The order cetacea includes modern-day whales, dolphins, and porpoises. these marine mammals share common characteristics that have led scientists to make a conclusion about their evolutionary history. cetaceans:
lack gills and must breathe air
give birth to live young rather than lay eggs
have fin bones that are similarly shaped to limb bones
have spines that flex up and down rather than side to side
the characteristics of cetaceans provide evidence that
a.
they evolved from land mammals.
b.
the theory of evolution is incorrect.
c.
they evolved from air-breathing fish.
d.
the bodies of their ancestors never changed.

Aresearcher designed an investigation to test what effect eating different types of food would have on blood insulin levels. she selected 10 male subjects who were all 25 years of age and in good health. the experiment took place over 3 days. at 8: 00 a. m. on each day, the subjects ate a meal consisting of only 1 type of food. they had their blood insulin levels measured after consuming the meal. on day 1 they ate a high fat diet, on day 2 they ate a high protein diet, and on day 3 they ate a high sugar diel what is the independent variable in this experiment? a the age of the subjects b the blood insulin level c the type of food consumed d the time of day the meal was consumed