What kind of bond holds together atoms within a molecule?

Aperson with age is more likely to catch diseases that healthy people usually don’t catch. what are these infections called?

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming

Which example would the nurse consider to be a part of systems thinking theory?