They study the human body
Answer:
Blood is carried away from the heart by arteries. Blood that is rich in oxygen. Blood that is low in oxygen is returned to the heart by veins. there is more pressure in arteries than in veins.
Answer:
Pyramid is a good representation of energy flow in an ecosystem because the shape of pyramid is wider at the bottom and pointed at the top. In the ecosystem, population of plants are maximum so it is placed at the bottom of the pyramid while the organisms such as tertiary consumers are placed at the top of the pyramid due to low in population. So pyramid is a good representation.