Which term describes free-floating, photosynthetic microorganisms in the oceans that are important for producing oxygen? a. phytoplankton b. yeasts c. pathogens d. protozoa

The organism shown is a free-living one that is anchored to the bottom of ponds and streams during one stage of its life cycle what is the common name for the group to which this organism belong

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?

Light waves can move through , but they travel fastest when they move through a(n) .