In a forest ecosystem, a species of bird was introduced. the birds had few predators, and for a period of time its population rose steadily and then roughly leveled off. which of the following conclusions provides the best explanation for this phenomenon?
a. a predator of the birds entered the ecosystem, causing the bird population to level off.
b. migration of birds into the ecosystem began to decline, and emigration began to increase.
c. another species of bird was introduced, and the two species competed for nesting sites and food.
d. the ecosystem reached its carrying capacity, and was not able to support continued population growth.

d. The ecosystem reached its carrying capacity, and was not able to support continued population growth.

Explanation:

The carrying capacity can be defined as the maximum population size of the species that habitat or ecosystem can support or sustain on the basis of availability of food, water and other necessities. This is an important factor which keeps a balance of the population of a species in a particular region or ecosystem.

On the basis of the above information, The ecosystem reached its carrying capacity, and was not able to support continued population growth is the correct option to level off the rising populating of the birds.

The correct answer is option d. "The ecosystem reached its carrying capacity, and was not able to support continued population growth".

Explanation:

The carrying capacity of an ecosystem is defined as the maximum number of organisms of a certain species that can be supported indefinitely taking into account the resources that the ecosystem can provide. In this example, a species of bird flourished because of the lack of predators but the population started to leveled off. It is likely that the ecosystem reached its carrying capacity, and was not able to support continued population growth. The increased number of birds had to compete for the resources, which resulted in a leveled off of its population.

C

Explanation:

A food chain outlines who eats whom. A food web is all of the food chains in an ecosystem. Each organism in an ecosystem occupies a specific trophic level or position in the food chain or web. Producers, who make their own food using photosynthesis or chemosynthesis, make up the bottom of the trophic pyramid.