Assume that a black guinea pig crossed with an albino guinea pig produced 5 black offspring. when the albino was crossed with a second black guinea pig, 4 black and 3 albino offspring were produced. what genetic explanation would apply to these data?

As a matter of terminology, albino guinea pig actually refers to a white fur guinea pig, whose genotype is homozygous recessive (bb).

If it crossed with a black fur guinea pig and gave 5 black fur offsprings, there is a good chance that the black fur parent is homozygous dominant (BB).
The Punnett square would be as follows:

       B      B
b     Bb   Bb
b     Bb   Bb
So they are all heterozygous black fur offsprings.

However, it is not impossible that the black fur parent be heterozygous, namely

       B      b
b    Bb   bb
b    Bb   bb

Giving a 50% chance on each colour.  Thus it is possible (with probability 1/32) that all five offsprings are heterozygous black fur if one of the parents was heterozygous.

In the second case, a homozygous recessive and a homozygous dominant parent will never give a white offspring.  So it is sure that the black fur parent is heterozygous, with the following Punnett square:

       B      b
b     Bb   bb
b     Bb   bb

With a 50% probability for each of Bb (black fur) and bb (white fur).
the distribution 4,3 demonstrates this perfectly.

No that answer is wrong. you have written the function of mitochondria in chloroplast and function of chloroplast in mitochondria.