A virus was introduced to control a rabbit population. At first, the rabbits died in large numbers, but the death rate decreased over time. Which of the following
explains the decrease in the rabbit death rate?
The rabbits that were originally infected with the virus have been dead for many years
Young rabbits learned to avoid being infected with the virus
The lifespan of this virus is too short to affect the rabbits over a long period of time
Natural selection favored rabbits that are resistant to the virus

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.