11. When cold temperatures are produced in a chemical reaction, the reaction is known as
a. exothermic.
b. endothermic.
c. suspension

According to the theory of punctuated equilibrium, at what rate does speciation occur? species change depending on the rate of natural selection. after periods of stasis, new species evolve relatively rapidly. species change slowly and eventually form new species. some species change quickly and others change slowly to balance the overall rate.

Which of the following statements about archaea and bacteria is true? a. neither is single-celled. b. they both have nuclear membranes. c. neither reproduces by binary fission. d. they both lack a nuclear membrane.

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material