Answer: B. right atrium --> right ventricle --> left atrium --> left ventricle
Explanation: Deoxygenated blood enters the superior vena cava and inferior vena cava and collects it on the right atrium. It is then pumped up through a valve and enters the right ventricle. Then it is transported by the pulmonary artery to the lungs to become oxygen rich blood. From the lungs oxygenated blood enters into the pulmonary vein and back into the heart and goes inside the left atrium. The blood is pumped again through a valve going to the left ventricle and transported to the body through the aorta which distributes oxygen rich blood.
When air is heated up the molecules spread out and move faster, so heat rises because it is less dense than the cooler air around it.
Sustain Life and Growth
Air consists one of the main life-sustaining gas called oxygen. Almost all living things breathe in and breathe out this air. Nitrogen and Carbon dioxide are also other gases that are vital for plants and their growth.
Combustion
Apart from this, air supports burning or combustion. The oxygen present in air help in burning of the fuels to basically carry out activities like cooking food, running industries and vehicles as well as generating heat and electricity.
Temperature Control
Another important aspect of air is that it helps in maintaining the temperature on the earth surface by circulating hot and cold air. Air acts as a conductor of heat as well. Even phenomena such as water cycle are dependent on air.
Supplier of Energy
Air which consists of energy is one of the main suppliers of energy. Living things are made up of cells and these cells extract oxygen within the blood to produce energy usually in the form of ATP. This biochemical generation of ATP is essential to maintain life on the earth.
Photosynthesis
Carbon dioxide, which is a component of air is used by plants during the process of photosynthesis. Here oxygen is also released by plants. And we already know how vital oxygen is.
