Final answer:
Maize lost much of its genetic diversity due to a combination of a genetic bottleneck, strong artificial selection by humans, and the random effects of genetic drift; hence, options a, b, and c all correctly explain the observed loss in genetic diversity.Hence,option 5) a, b, and c are correct.
Step-by-step explanation:
The question addresses why maize had lost much of its genetic diversity 4400 years ago, which we can explain by considering a combination of factors including a genetic bottleneck, artificial selection, and genetic drift. A genetic bottleneck occurs when a sudden environmental event drastically reduces the size of the population, leading to a decrease in genetic variability. Artificial selection is a human-driven process where certain traits are selected for by breeding individuals with those desired traits, leading to a reduced genetic diversity as other alleles are not passed on. Moreover, genetic drift refers to changes in allele frequencies due to random events, which is more significant in small populations and can lead to a loss in genetic diversity over time.
Therefore, the correct answer to the question regarding the loss of genetic diversity in maize would be that it is due to a combination of a genetic bottleneck, strong artificial selection, and genetic drift, which correlates to option 5) a, b, and c are correct.