Answer should be short and to the point. Because questions in general science and ability are of 5 marks. So no need to in the depth. One page is sufficient to get full marks.
What should be in a paragraph?
Definition of what is being asked.
Sources/origin of that thing.
Impacts of that.
types/categories/related to
prevention/measure/result
Describe your answer with these type of sub headings, each sub heading with respect to each single mark. It will be fruitful if any relative figure or diagram is drawn with the answer. Examiner will come to know that you understand and know about the question.
Hence, it will help examiner to do not dig into your answer for any important point.

Secondly, try to equally distribute time among all answers. If one answer is explained well and other in short, this will give overview to examiner that these are weak areas of candidate. Therefore, equally distribute time and keep balanced approach in each answer.