Question

polyploidy is when an organism ____________ and occurs during ____________.
has an extra set of chromosomes; sympatric speciation
has one extra chromosome; allopatric speciation
has a reduced set of chromosomes; sympatric speciation
has an extra set of chromosomes; allopatric speciation

Explanation:

Polyploidy is the condition where an organism has one or more extra sets of chromosomes (not just one extra chromosome, and not a reduced set). Sympatric speciation can occur due to polyploidy (e.g., in plants, where errors in meiosis lead to polyploidy within the same geographic area), while allopatric speciation is due to geographic isolation. So the first option correctly defines polyploidy (extra set of chromosomes) and the associated speciation type (sympatric).

Answer:

A. Has an extra set of chromosomes; sympatric speciation