I think the correct answer is a
Mutations can occur before, during, and after mitosis and meiosis. If a mutation occurs in cells that will make gametes by meiosis or during meiosis itself, it can be passed on to offspring and contribute to genetic variability of the population
Answer is D.
Waste products from metabolism are carried by the circulation to the kidneys, which filter them out if the blood to be excreted in urine.