Answer:
C) It involves interactions between biotic and
abiotic factors.
Explanation:
Ecosystems need energy imput, need both consumers and producers, and can exist on land, lakes, rivers and oceans.
Answer:
The systemic circulation is the part of the circulation system which is contrasting to the pulmonary circulation as it includes the movement of the oxygenated blood from the left ventricle to the capillaries present in the tissues through the arteries.
It also includes the return of the deoxygenated blood from capillaries of different veins to the right atrium of the heart. It provides all the blood required for carrying the nutrients and oxygen to the parts of the body to heart and heart to different parts of the body
Answer:
the later stages are small and the tool materials are of better quality than the previous stages.
Explanation:
The stone scrapers and the choppers found at the site of Zhoukoudian points out the fact that Peking men devised several tools for various purposes and to accomplish different tasks. The stones and the bones used to make the tools used to be charred by using the fire. This also indicates that the Peking men had discovered the uses of fire and they used fire for various activities.
