Sexual reproduction causes genetic variation because of -

Correct answers: (c) Shuffling of genes or (d) All of the above

Explanation

Offspring of sexual reproduction differ because their genes are reshuffled: by crossing over and independent assortment in meiosis, and by the joining of chromosomes from two parents at fertilisation. These are changes in how genes and chromosomes are combined.

The book's key counts all three options, (d); strictly, genes do not blend.

The book gives (d) All of the above; strictly, genes do not blend, so (c) is the precise answer. Both are accepted here.