Answer: D) Tree roots improve soil water retention
There are many reasons which states that deforestation increases the risk of flood. First , some water stay on the leaves and evaporates in to the atmosphere. Second, tree leaves reduce the impact of raindrops on the soil which causes less soil erosion.
Third, tree roots absorb water from the soil, which make the soil dry and it absorb more water rainwater. The roots of tree hold the soil in place and reduce the movement of sediment which reduce the capacity of river to break its banking. Thus, reducing the chances of flood.
Answer:
b) from a region of high pressure to a region of low pressure
Explanation:
Blood flow is measured in blood volume per unit time. It is the movement of blood through an organ, tissue or vessel. It is initiated when ventricles in heart contract leading to its ejection at high pressure. Major arteries receive this blood and they further transport it at high pressure to smaller arteries, arterioles and capillaries. Hence arteries have thick walls to withstand this pressure. The pressure decreases when blood reaches to veins hence their walls are not that thick. Hence, blood flows from a region of high pressure to a region of low pressure.