How many independent variables does a good investigator use in his or her experiment?

You should generally have one independent variable in an experiment. This is because it is the variable you are changing in order to observe the effects it has on the other variables.

HOPE THIS HELPEDX

b. a lightning bug, plug of grass, and a worm

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