If an organism is homozygous for a particular trait, the organism A. has extra alleles on both chromosomes in a chromosome pair. B. has the same allele on both chromosomes in a chromosome pair. C. is missing alleles on the chromosomes in a chromosome pair. D. has different alleles on the chromosomes in a chromosome pair.

B. Has the same allele on both chromosomes in a chromosome pair.

Here is why:

Homozygous means the same, while heterozygous means different. If both of the same alleles are on both chromosomes, then it will be a homozygous.

There can be two types of homozygous alleles.

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Homozygous Dominant: BB

Homozygous Recessive: bb

Notice in both of these they were the same alleles.

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Heterozygous: Bb

Notice how both are different alleles.

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Below I have attached a diagram of a Punnett square I have made.

On the left is a homozygous recessive allele pair.

On the top is a heterozygous allele pair.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

it would be rhyolitic hope this