Nucleotide!
When attached in a polymer, they become a nucleic acid.
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.
The three mechanisms which regulate the heart are endocrine, cardiovascular and Sinoatrial nodes.
The endocrine system consists of the glands and hormones of the human body. The cardiovascular system is the organ system which is responsible for the circulation of the blood around the body and the oxygenation of the body's tissues. The sinoatrial node (SA node) generates the electrical impulses and is considered the natural pacemaker of the heart.
C. The brain sends messages to the spinal cord
