Which feature is common to prokaryotic and eukaryotic cells?

organelles
cell nuclei
complex structures
cell membranes

The right answer is cell membranes.

A cell necessarily has a membrane, a cytoplasm and genetic information. However, the cells are different: there are prokaryotes, eukaryotes.

A prokaryotic cell is a cell that does not have a delimited nucleus, the genetic information is free in the cytoplasm. For example, the bacteria are prokaryotic cells. Conversely, eukaryotic cells have an envelope-bound core. Inside this one are included the animal and plant cells.

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.