Afferent neurones connect? A the brain and spinal cord to muscles
B sense organs to muscles.
C one sense organ to another sense organ
D sense organs to brain and spinal cord

Can someone explain to me the answer because I'm confused.

These neurons are located in the central nervous system (the brain and spinal cord). Afferent and efferent neurons have to work together in order to sense and respond to stimulus, but they don't directly connect. Association neurons bridge the gap to relay information between sensory and motor neurons.

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.