A scientist has been tracking and studying a population of deer in Yellowstone National Park. He surveys the population every six months. Usually, the population is thriving and has a gene pool with a wide variety of traits. But during one six-month period, an event occurred that affected the population, and when the scientist returned, the amount of genetic variation had decreased significantly. Which of the following is most likely the event that occurred to change the population? Yellowstone National Park expanded its borders.
A population of wolves was introduced into Yellowstone National Park.
The amount of disease in the deer population decreased.
More grass and shrubs were planted in Yellowstone National Park.

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

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.

copper and glass have high electrical conductivity