Question

multiple choice question
haploid cells contain

a single set of chromosomes.

a single pair of chromosomes.

a single chromatid for each chromosome.

a single nuclear membrane.

Explanation:

To solve this, we recall the definition of haploid cells. Haploid cells (like gametes) have a single set of chromosomes (n), as opposed to diploid cells which have two sets (2n). The other options are incorrect: a single pair would imply two (diploid - like), chromatid number isn't the defining feature of haploidy, and nuclear membrane presence/number isn't related to haploidy.

Answer:

A. a single set of chromosomes.