A fungus with white spores cross fertilizes a fungus with black spores. If 10% of the progeny bear white spores while 90% of the progeny bear black spores, what must be true? A.
The trait for spore color is determined by exactly one gene.

B.
The trait for spore color is determined by more than one gene.

C.
The allele for black spores is dominant over that for white spores.

D.
The allele for white spores is dominant over that for black spores.

C.

Explanation:

Since there are more of an outcome of black spores it would make sense that this trait is dominant.

White spores seem to be recessive in this case too.

I also suspect the parents are both heterozygous. They both carry one trait for black and one for white.

Hopefully this is correct. Have a great day.

where is the scientific experiment?

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.