Answer:
The main function of the circulatory (or cardiovascular) system is to deliver oxygen to the body tissues, whilst simultaneously removing carbon dioxide produced by metabolism.
The practically boundless varieties of antibodies can be produced using one arrangement of qualities is introns and exons take into account one quality coding to really code for a wide range of antibodies. Amid the procedure of RNA grafting, introns are evacuated and exons joined to frame a bordering coding succession.
This means that it only allows for select materials to be able to move across it and not all molecules and other substances floating in the external environment. The proteins and the phospholipid Bilayer help to contribute the selectivity of the membrane.