When a male donkey is bred with a female horse, the offspring produced is a mule, which is healthy but sterile. karyotyping experiments have revealed that horses and donkeys have different numbers of chromosomes, 64 for horses and 62 for donkeys. the mule, therefore, has 63 chromosomes. knowing this, what is the best explanation for the inability of mules to produce offspring?

In an organism with even number of chromosomes, the chromosomes become half in number during gamete formation . For example: A horse has 64 chromosomes. Its gametes will have 32 chromosomes. The gamete formation process in mules will fail because of its odd number of chromosomes.

63 chromosomes would not be able to divide perfectly for gamete formation. This will happen because proper pairing of homologous chromosomes will not occur during meiosis I. Synapsis is the pairing of homologous chromosomes before they segregate and chromosomal crossover also occurs during this stage. In mules, some gametes will be formed with missing chromosomes and some will have extra chromosomes because synapsis formation will be abnormal. Hence, mules are not able to produce viable gametes and are sterile.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.

i believe the answer is snake.