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

Can someone me with 6 to 10 plz this is for masteries test.

Uranium can supply energy for the worlds electricity without admitting harmful greenhouse gases which of these statements best describes an outcome of uranium mining

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.