Answer:
The biologist is studying about the ecological community.
Explanation:
The ecological community refers to the community in which population of different types of species survives together. As the biologist is observing about the interaction of different populations of Pennsylvania region, it can be inferred that the he is studying about the ecological community of Pennsylvania region.
The population surving in the community interact with each other through different modes of interaction. It may either parasitic, or mutual, or competitive or predication or commercialism.
Chorus and vocal soloists in the final movement.
The functions of eyes parts are as follows:
Retina: The rays of light focused on the retina by the cornea and lens. The retina produces an image which is sent along the optic nerve of the brain.
Iris: It changes the size of pupil and allows different amount of life to enter the eyes.
Pupil: The light enters to the eyes through it.
Cornea: It forms the outer coating of the eyeball and covers the iris and pupil.
Lens:
