Which method involves breeding animals in a controlled environment?

Environmental differences within ecosystems are generally caused by

Acertain species of fish can have either long or short fins. the allele for long fins is dominant over the allele for short fins. a heterozygous, long-finned fish is crossed with a homozygous, short-finned fish. of the offspring, will have long fins and be , and will have short fins and be .

Which macromolecule catalyzes chemical reactions this be considered enzyme chemical reactions thus he considering enzymes