Of the different sources of genetic variability, which one causes the variation in the combinations of homologs from paternal and maternal linage found within a haploid cell? (a) independent assortment(b) crossing over(c) random fertilization(d) mutation

Crossing over.

Explanation:

Crossing over may be defined as the phenomena of exchange of the genetic material between the non- sister chromatids of the homologous chromosomes. The crossing over occurs at the pachytene stage.

The crossing over may provide a source of genetic variation as it can create variation in the homologs of paternal and maternal lineage, present within a haploid cell. This crossing over occurs during the process of synapsis.

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.

the answer is :