All of the substances are which cause inheritable changes in genetic material.
a) agents
b) mutagens
c) pathogens
d) vectors

B) mutagens

Explanation:

Mutagenic substance is any substance that can cause mutations in a cell. In other words, when a cell is exposed to a mutagenic substance, that substance has the power to cause changes in the genetic material that are not repaired by the repairing enzymes and become inheritable characteristics, that is, it causes mutations that are inherited.

These substances can be divided into three types: chemical agents, physical agents and biological agents.

they are known to reach a speed of 21 miles per hour

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.