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.
Compare it to respiration in the human body or like how a car converts fuel to work or how a machine works because of electricity
Unequal reproductive success - Accumulation of favorable traits over time. Unequal reproductive success. heritable traits best suited to the local environment are more likely to survive and reproduce. Accumulation of favorable traits over time.
The process in which a gene from one organism is inserted into the DNA of another organism is called genetic engineering or recombinant DNA technology. It is done to transfer the desirable trait of one organism to another to produce a better organism.