30 POINTS!! After 70 years of absence, the gray wolf was reintroduced to Yellowstone National Park in 1995. After 1995, the elk population, which had been exploding, began to decline in numbers. Willows and aspen trees began to grow more abundantly on riverbanks. The beaver population began to increase, and songbirds were more abundant in the grasslands and riverbanks. What is the MOST LIKELY explanation for these events after the wolf was reintroduced?
A
The wolves began preying on the elk, and the beaver started using the trees to make lodges.

B
After the gray wolves came back to Yellowstone, the carrying capacity of the ecosystem increased.

C
The wolves' reintroduction altered the limiting factors for the elk, the beavers, the trees, and the songbirds.

D
The wolf's presence caused a decrease in the elk population, which allowed the riverside trees to grow more abundantly, which provided logs for the beavers' lodges and habitats for the songbirds.

The most likely explanation would be that the presence of wolves caused a decrease in the elk population, which allowed the riverside trees to grow more abundantly, which provided logs for the beavers' lodges and habitats for the songbirds.

The wolves introduced to the ecosystem must have been preying on the elk population, leading to a reduction in their population size.

Reduction in the population size of elk means that less predation on riverside trees, making them grow more abundantly.

The thriving of riverside trees provides logs for beavers' lodges and nest-building habitats for songbirds.

More species interaction in the ecosystem can be found here:

the national environmental policy act (nepa) is a united states environmental law that promotes the enhancement of the environment and established the president's council on environmental quality (ceq). the law was enacted on january 1, 1970. to date, more than 100 nations around the world have enacted national environmental policies modeled after nepa.