Answer:
The return of blood to the heart is assisted by the action of the skeletal- muscle pump. As muscles move, they squeeze the veins running through them. Veins contain a series of one-way valves, and they are squeezed, blood is pushed through the valves, which then close to prevent backflow.
Answer:
In the food chain, producer makes the base, primary and secondary consumers are present in the middle and tertiary consumers is present on the top.
Explanation:
Producers are the organisms which makes their own food such as plants. They are placed at the base due to high population. Primary and secondary consumers are placed in the middle due to less population than producer and tertiary consumers are placed on the top due to very low population.
The more light absorbed, the quicker the photosynthesis rate.
Its A. ribosomes and lysosomes i know its lysosomes but im not 4 sure about ribosomes hope this helps......
