Your heart pumps blood so it can circulate to your tissues as well as get oxygen from your lungs, if your heart can’t pump blood well i.e. heart attack you can feel short of breath
Answer:
<em>In a population, natural selection acts on phenotype of individuals.</em>
Explanation:
Natural selection tends to favour those organisms of a population which carry traits that allow them to be better adapted to the environment and these traits are passed on to their offsprings. Natural selection tends to act on the phenotype of the population whereas evolution is the phenomenon which changes the allele frequencies. Natural selection acts on individual organisms of a population whereas the change in populations, on the whole, arises due to evolution.
When we drink less water or we are dehydrated the body will compensate for 1-2% of the total amount of water by creating a sensation of thirst. The kidneys, brain, hormones and glands work in co-ordination monitoring the amount of water consumed to the amount of water lost.
The hypothalamus gland regulates the temperature of our body and balances the processes to control the amount of fluids in body. On detecting less amount of water in blood the hypothalamus gives signals for releasing the anti-diuretic hormone which causes kidneys to remove lesser amount of water from the blood. As a result of this we urinate less and the urine is concentrated dark in appearance. The brain also signals to consume water or liquid to bring the hydration level of the body to normal.
As blood enters the artery, the walls of these vessels expand and contract, which can be felt as the pulse where the arteries run close to the body surface.
It is common to detect the pulse with a few fingers placed on the radial artery on the wrist, or the carotid artery in the neck.
Because the walls of the arteries pulse whenever the left ventricle contracts, the pulse rate generally indicates the cardiac function, which is normally between 50 and 85 in a healthy adult.
Pulse is usually defined as the rhythmic dilation of the arteries due to flow of the blood caused by heart contractions. The measurement of the pulse rate can be used for the diagnosis of serious disease such as cardiac disease.
