D is the correct answer i think.
The reason it's so important is because say you were doing push ups. Most people hold their breath will doing any exercise, and that is really bad for you. The reason why you have to exhale completely is because if you don't, you can/will pass out because your brain won't have enough oxygen to pass down for your muscles to work properly.
The stabilization of a radioactive parent element into a stable daughter element occurs through the process of radioactive decay. The unstable atomic parent emits radiation and loses its energy. This leads to the formation of a daughter element, which is less radioactive or is stable.
Answer: The most reason was that cell-to-cell communication and the different chemical compositions of the cell walls of plant, fungi, and bacteria restricts the intercellular communication to their own species.
Explanation: