The evolution of organisms that use oxygen in their respiration was possible only because of the action of a group of bacteria that produced oxygen and changed the earth's atmosphere from an anoxic one to one rich in oxygen. that group of bacteria was:

What are the four basic classes of organic molecules how do they differ structurally and functionally

Darrel conducted an experiment with the following procedure: fill two cups with ice water. place an uninflated balloon snuggly onto your left index finger. blow a little air into an identical balloon, and place it onto your right index finger. place both fingers into the cups of ice water. darrel noticed that his right finger felt warmer in the ice water than did his left finger. which of the following does the experiment show? a. air is a good radiator of heat. b. air is a good insulator of heat. c. air is a good conductor of heat. d. air is a good convector of heat.

The bacteria found in soil is usually harmful and measures are taken to remove any traces of microorganisms. true or false