Which of the following organisms first introduced oxygen into earth's atmosphere?
a. cyanobacteria
b. methanogens
c. early protozoans
d. plants
e. green algae

1. environmental factors, such as ph and temperature, can affect the function of an enzyme. a. true b. false 2. which of the following is an organic molecules (ex. vitamins) that an enzyme? a. coenzyme b. product c. active site d. substrate 3. how do enzymes effect the speed of a chemical reaction? a. they speed it up b. they slow it down c. they have no effect on the speed of a reaction 4. during a chemical reaction, an enzyme is used up so that it can only be used one time. a. true b. false 5. which of the following results from a chemical reaction that is catalyzed by an enzymes? a. active site b. product c. substrate d. coenzyme

Drag each tile to the correct box. match the given symbol or molecular formula to the term that best describes it. element -organic compound -inorganic elemental molecule -inorganic compound -answers given: so2, k, ci2, c6h6

Which statement about dna replication is true? a. eukaryotes only have one circular chromosome that unwinds at multiple locations. b. eukaryotes can only replicate one segment of a chromosome at a time. c. prokaryotes can only replicate their single circular chromosome in the nucleus. d. prokaryotes only have one origin of replication to initiate replication.