Final answer:
Physiological adaptation involves physiological changes in living organisms that help them cope with their environment or a threat. Examples include increased heart rate in a threatening situation and the immune response against microorganisms.
Step-by-step explanation:
Physiological adaptation refers to the physiological changes that living organisms undergo to cope with their environment or a threat. It can involve various bodily responses, such as an increase in heart rate during a threatening situation to supply more oxygen to the muscles for better performance. Another example is the immune response that helps organisms fight off invading microorganisms.