Tendons :may also attach muscles to structures such as the eyeball. A tendon serves to move the bone or structure. A ligament: is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.
Answer: Viruses, although not living things, do show some characteristics that they are living. Because they can't reproduce by themselves (without a host), viruses are not considered living. They are made of proteins and glycoproteins like cells are. They contain genetic information needed to produce more viruses in the form of DNA or RNA.
They are acellular, that is, they contain no cytoplasm or cellular organelles. They carry out no metabolism on their own and must replicate using the host cell's metabolic machinery.
Usually during exercise, unlike during rest times the muscle cells need to respire more. So they need more oxygen and glucose for energy and the carbon-dioxide produced as waste must be removed quickly. So when person gets tired or breathes heavily during intensive workouts means they are in need of more oxygen. So the cells starts performing anaerobic(lactic acid ) respiration even though it releases less energy.
