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.
The group in which a star is classified according to its spectrum, especially using the Harvard classification.
Answer: (A) a membrane‑bound organelle with stacks of thylakoid discs called grana.
(E) the main site of photosynthesis in a plant cell.
Explanation:
The plant chloroplast is a large organelle, it is bounded by a double membrane like structure that is chloroplast envelop.
The chloroplast consists of chlorophyll pigment which traps the light energy from sun and converts it into chemical energy in the form of ATP. Thus the chloroplast is the main site for photosynthesis. Including the inner and outer membrane structure it also posses the third internal membrane structure which is called as the thylakoid membrane. The thylakoid membrane forms the network of flat discs which are called as thylakoids, the thylakoids are arranged in stacks which are called as grana.
The thylakoid membrane is the center point for the synthesis of ATP through a chemiosmotic process.
