Human population growth accelerated in recent centuries mostly because of a. the bubonic plague. b. better hygiene and food. c. the discovery of electricity. d. improved efficiency of fuel use.

The correct answer is b. better hygiene and food.

Explanation:

Human growth rate has accelerated in recent centuries because of the availability of better nutrition, hygiene, and health care. Unhygienic condition and lack of health care was the reason for the high mortality rate in early times which helps in making a disease epidemic that kills thousands of people in a short period.

But due to advances in technology in food, and health field people started to follow better hygiene and getting good nutrition and health care which helped in increasing the life expectancy in people during recent centuries. So the right answer is b.

i think that you are smart and you should fit for it out

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.