Because of the heart beating it makes a thunk noise. Your heart has a suction affect which makes the noise.
Answer:
The carbohydrate is one of the most important nutrients needed in the diet of an athlete, as they are important to increase their performance during physical activity and exercise.
Carbohydrate is the main source of energy needed by the brain and by our body for its proper functioning. when carbohydrates are eaten up they are broken up into small sugar unit called as glucose.
These glucose unit are stored in the muscle and liver in the form of glycogen to be used as a fuel at the time of exercise and during intense physical activity. It is known to enhance the athlete performance by delaying the fatigue and help them to compete for a longer period of time.
The right option is; ice sheets
The only ice sheets that exist today are found in Greenland and Antarctica.
Ice sheets are masses of glacial ice that covers more than 50,000 square kilometers. The only ice sheets that exist on earth currently are found in Greenland and Antarctica. This two ice sheets contains most of the freshwater ice on earth. Ice sheets are formed during winter when snow falls and partially melts over the summer. The snow then accumulates to form dense and thick masses of glacial ice.
C. their skin
they have small areas where air can be taken in and released