A scientist has an unidentified substance that she believes to be one of the four substances in the table above.

In which blood vessels would you expect to find the greatest amount of exchange

Which is the best example of natural selection? Some insects in a population survive temperature changes and pass their traits on to their offspring. A deer population is rapidly killed off by a forest fire.

Which of the following organisms has a closed circulatory system? a. Sponges b. Cnidarians c. Nematodes d. Insects e. Vertebrates

Which of these is not a feature that links "dinosaurs' to modern day extant birds"? a. A furcula b. Feathers c. S-shaped neck d. Nasal turbinates e. The flight stroke

How is ruminants stomach different from human stomach?

How has global temperature changed over the last 1000 years

What factors determine soil consistence?

What are the levels or organization in biology?

In what grade do you take biology I took it in 6th grade, just wondering

What type of mutations do scientists look for in a molecular clock