Except for a pairing of sex chromosomes, homologous chromosomes.

a. carry the same genes
b. are the same shape
c. are the same length
d. all of the above

Homologous chromosomes carry the same genes and have the same shape and length, so all the choices are correct.

Explanation:

The homologous chromosomes are so called because each of them has the same DNA molecule, giving rise to the same genes, distributed in the same location within the chromosome.

Somatic cells are diploid, which means that the genetic information that determines specific characteristics is distributed in pairs. Each of the chromosomes that form a pair comes from the father and mother, and the members of a pair are known as homologous chromosomes.

The homologous chromosomes are characterized by having the same shape and size, and contain the same genes, although the information contained in them —the alleles— may be different. Hence the possibility that one allele is dominant and another recessive on two chromosomes of a pair.

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