Which is true for the beginning of the Cenozoic era?

A.) Mammals and dinosaurs lived together.

B.) Mammals first appeared.

C.) Dinosaurs had killed all mammals.

D.) Dinosaurs were extinct.

Which of these is true of echinoderms a. They have heads. b. They have radial symmetry. c. They have shells. d. They have smooth skin.

Why are free radicals so reactive? If free radicals are so reactive, why are paramagnetic substances such as O2 stable?

Since metabolism involves the synthesis and breakdown of non-protein cell components like mono - and polysaccharides, lipids, and ATP, there is not much role for gene mutations to influence the process. a. True b. False

What is a hypothesis? a conclusion made based on facts a suggested answer to a problem a widely accepted idea information collected from experiments

How do biofuels work?

A pregnant woman at 37 weeks gestation calls the clinic to say she thinks that she is in labor. the nurse instructs the woman to go to the health care facility based on the client's report of contractions that are:

A human nose is capable of detecting how many basic odors? a. 20 b. 40 c. 49 d. 50

Why is a control necessary to have when designing an experiment?

Why are there many separate ecosystems in a rainforest

Describe several ways in which the cheek epithelial cells differed from the potato, tomato, and onion cells? be specific