During which process does a single-celled organism divide to form two new organisms?

Asexual reproduction is the correct answer because it is a process through which a single-celled organism can divide and produce two genetically identical offspring without the involvement of gametes or fertilization. In asexual reproduction, the organism undergoes a process such as binary fission, where it duplicates its genetic material and then splits into two new organisms, each with the same DNA. This type of reproduction is common among bacteria and some protozoa.

In contrast, sexual reproduction involves the combination of genetic material from two parents, leading to offspring that are genetically diverse. Meiosis is a type of cell division that reduces the chromosome number by half and is crucial for sexual reproduction, specifically in the formation of gametes, but it does not directly result in the production of new organisms. Fertilization is the process where gametes combine, leading to the creation of a zygote, which will develop into a new organism. Thus, the nature of asexual reproduction being a straightforward division leading to two organisms distinguishes it clearly from the other processes mentioned.