Human hair color is a classic, if oversimplified, example of recessive epistasis. red hair is caused by a recessive allele r. however, if an individual has a dominant r allele, they may have either brown or blonde hair depending on whether they have a dominant b allele (which causes brown hair), or are homozygous for a recessive b allele (which causes blonde hair). the b and r loci are on located on different chromosomes. if a couple with genotypes bb; rr and bb; rr have children, what hair colors and in what proportions are expected among their children?

1 Brown: 1 Blonde: 2 Red

Explanation:

According to the given information, the recessive allele "r" gives red color to hair but is epistatic to alleles B and b. Therefore, the genotype with two copies of the "r" allele would have red-colored hair. The genotypes with at least one copy of "B" and “R" alleles each would have brown hair while the "R" allele would give blond hair in presence of allele "b".

Therefore, a cross between BbRr and bbrr would produce progeny in following phenotype ratio= 1 Brown: 1 Blonde: 2 Red

your answer should be c) enjoy!

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.