<span>Every living organism begins life as a single cell. Unicellular organisms may stay as one cell but they grow too. Multicellular organisms add more and more cells to form more tissues and organs as they grow. </span>
A- the antlers and horns are structural adaptations. The fighting is a behavioral adaptation.
Antlers and horns are physical adaptations that some mammals have acquired over time. However, fighting is not a physical feature but a behavioral adaptation used to beat other males during mating season.
Hypertonic solution, such as increased salt (NaCl) from diet, or from hyperglycemia as in uncontrolled diabetes.
Evolution would be the answer you may be looking for.
