This is cyclic change because the population is consistently going up and back down.
Answer: option C) cowpox and smallpox are caused by the same virus
Explanation:
Cowpox is a skin disease that affects cattle. It is caused by an Orthopoxvirus, with lesions occurring principally on the udder and teats of the animals.
Human infection may occur from touching infected cows, and thus giving immunity to smallpox (an acute infection caused by the same poxyvirus, in HUMANS)
So, Jenner's successful use was because cowpox and smallpox are caused by the same virus
The correct answer is - 1) inverted pyramid, with a narrow base representing a small number of young individuals.
The populations that are decreasing are usually population in countries that are highly developed. The conditions for living are excellent, the medical care on high level, life expectancy very high, but the birth rates very low.
In this type of conditions, there's smaller and smaller number of young individuals, with the middle aged population being much bigger, and the older population being constantly on the rise. This will give the age-structure histogram a reverse shape than what it is supposed to have, it will be similar in appearance like a inverted pyramid, meaning that the population is aging and that it will be constantly on a decline in the future.
A transverse section cut is a cross section took by slicing, really or through imaging techniques, the body or any part of the body structure, in a horizontal plane, a plane that crosses the longitudinal axis at a right angle. In other words, it divides the body into superior and inferior parts which is also known as the top and bottom parts.