What is the primary goal of homeostasis in living organisms?

• To increase metabolic rate.

• To maintain a stable internal environment.

• To promote rapid growth and development.

• To adapt to external changes by altering internal conditions permanently.

Which of the following is an example of a variable regulated by homeostasis in the human body?

• External air pressure.

• Blood pH level.

• The color of skin.

• The amount of light entering the eyes.

Which term best describes an animal that regulates its body temperature primarily by absorbing heat from its surroundings?

• Endotherm.

• Homeotherm.

• Ectotherm.

• Poikilotherm.

What is a key characteristic of an endotherm?

• Its body temperature fluctuates with the environment.

• It relies on external sources to regulate its body temperature.

• It actively works to maintain a stable internal body temperature.

• It cannot survive in extreme temperatures.

When a human body becomes too hot, what is a primary response to lower its temperature?

• Shivering to generate heat.

• Blood vessels constricting to conserve heat.

• Sweating to allow heat to evaporate from the skin.

• Increasing metabolic rate to burn more calories.

If a person's internal body temperature drops too low, what physiological response helps to raise it?

• Increased sweating.

• Dilation of blood vessels.

• Muscle contractions (shivering).

• Decreased metabolism.

What is the main purpose of a negative feedback loop in the body?

• To amplify a change in a variable.

• To counteract a change and return to a set point.

• To permanently alter the body's set point.

• To initiate a new physiological process.

What is the primary role of insulin in regulating blood glucose levels?

• To increase the release of glucose from the liver.

• To make cells take in glucose from the blood.

• To break down glucose into simpler sugars.

• To convert glucose into fat for storage.

When blood glucose levels are too low, which hormone is released to help raise them?

• Insulin.

• Estrogen.

• Glucagon.

• Testosterone.

How does a positive feedback mechanism differ from a negative feedback mechanism?

• Positive feedback maintains a stable internal environment, while negative feedback causes fluctuations.

• Positive feedback counteracts a change, while negative feedback intensifies it.

• Positive feedback intensifies a change, while negative feedback counteracts it.

• Positive feedback is always beneficial, while negative feedback is always harmful.