Mass transit systems reduce air pollution.
a. true
b. false

Which statement best describes a keystone species? o a. it has littlelmenetic variation. it has an extremely high population. 0 b. 0 c. it remains unaffected by all environmental changes. od. it has a strong influence on the ecosystem. 0 e. it's the first species to populate a new ecosystem.

The term used to describe a disease-causing microorganism isa. virus.b. infection.c. pathogen.d. microbe.e. bacterium.

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna.