What is a biogeochemical cycle?
1. a process by which bacteria convert nitrates into nitrogen gas.
2. a process that converts light energy into chemical energy.
3. a process by which water enters the atmosphere by evaporating from the leaves of plants.
4. a process that recycles elements and other matter through the biosphere.

Answer : The correct answer is -

4) a process that recycles elements and other matter through the biosphere.

Biogeochemical cycle can be described as natural pathways for the recycling of the nutrients (which are primarily the chemical compounds) through biotic as well se abiotic compartments of an ecosystem.

It is broadly categorised into gaseous (such as oxygen, nitrogen, and water cycle) and sedimentary cycles (that include earthbound elements such as iron, calcium, sulphur etc).

Thus, elements and other matter are recycled through the biosphere in biogeochemical cycle.

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.