I believe the answer to 11 is that multicellular organisms are made up of multiple cells and unicellular organisms are made up of one cell.
The correct option is A.
Proactive interference refers to the tendency of the knowledge that one had learned previously to prevent one from subsequent learning. Thus, proactive interference is the difficulty that comes with learning new things due to the stuffs that one had learned before. For instance, an individual may find it difficult to learn Spanish because he has previously learn German.<span />
As the heart beats, it pumps blood through a system of blood vessels, called the circulatory system. The vessels are elastic, muscular tubes that carry blood to every part of the body.
Blood is essential. In addition to carrying oxygen from the lungs and nutrients to your body's tissues, it also takes the body's waste, including carbon dioxide, away from the tissues. This is necessary to sustain life and promote the health of all the body's tissues.
Reproductive isolating mechanisms are barriers which impeded mating (prezygotic) or prevent the hybrid from developing properly (postzygotic) but the overall effect is to cause speciation by making it difficult for two diverging species to share genes. So one kind of mechanical isolation could be the usage of contraceptives. As of temporal isolation, or behavioral isolation could be exemplified by people who suffer from diseases that cause separation (such as HIV or cancer). I hope that this is the answer that you were looking for and it has helped you.
DNA and RNA both produce proteins, but RNA copies itself and moves out of the nucleus while DNA stays inside the nucleus and produces proteins. Also DNA helps more in cell division, while RNA helps in making proteins.