Gas exchange in an echinoderm takes place through
a. book lungs.
b. skin gills.
c. lungs.
d. none of the above.

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

Which of the following are the ingredients that go into the plant and are needed for photosynthesis? select all that apply. 1.) soil 2.) seeds 3.) carbon dioxide 4.) minerals 5.) glucose (sugar) 6.) water 7.) light energy (sunlight) 8.) oxygen 9.) air

Which would be the most useful source of evidence to support mcneill's contention?