Which one of the following statements about human metabolism is not true?

Introduction / Context:
This question explores basic concepts related to human metabolism, particularly basal metabolic rate and factors affecting overall energy expenditure. Understanding which statements are correct and which are incorrect helps you build a clear picture of how age, heredity, and activity levels influence the way the body uses energy.

Given Data / Assumptions:

• The term metabolism refers to all chemical reactions that occur in the body to maintain life.
• Basal metabolism is a specific component of metabolism, measured under resting conditions.
• The statements discuss age, basal metabolism, and factors influencing metabolic rate.
• We are asked to identify the statement that is not true.

Concept / Approach:
Basal metabolic rate is typically defined as the energy required to maintain vital body functions at rest, such as breathing, circulation, and cell maintenance. In general, children and younger individuals have a higher metabolic rate per unit body weight than adults because they are growing and often have higher energy demands. Metabolism is influenced by several factors, including age, genetics, sex, body composition, and hormones. By comparing these accepted facts with the statements provided, we can identify the incorrect one.

Step-by-Step Solution:
Step 1: Examine the first statement, which claims that younger people generally have a slower metabolism than adults.Step 2: In reality, younger people, especially children and adolescents, often have a higher metabolic rate per kilogram of body weight due to growth and higher activity levels.Step 3: Therefore, the first statement contradicts standard physiological understanding and is not true.Step 4: Evaluate the second statement, which describes basal metabolism as the amount of energy needed for sustaining vital life functions, and recognize that this matches the usual definition.Step 5: Evaluate the third statement, which explains how basal metabolism is measured by the calories burned at rest when the body is inactive. This description is also consistent with standard practice.Step 6: Evaluate the fourth statement, which notes that metabolism is influenced by factors such as heredity and age, and confirm that this is widely accepted in physiology.Step 7: Therefore, among the options, only the first statement is incorrect.

Verification / Alternative check:
A helpful way to confirm is to recall that many weight management discussions mention that metabolism tends to slow with age. Children and teenagers often seem to eat more but gain less weight, because their bodies use more energy for growth and activity. In contrast, adults often find it easier to gain weight as their metabolic rate gradually decreases.

Why Other Options Are Wrong:
Basal metabolism definition: The description that basal metabolism represents the energy needed for vital functions at rest is accurate.
Measurement of basal metabolism: Measuring energy expenditure at rest in terms of calories burned is a correct characterization.
Influence of heredity and age: Genetic background and age are well known to affect metabolic rate, so this statement is true.

Common Pitfalls:
Some learners may misinterpret anecdotal experiences and assume that younger people have slower metabolism simply because they observe some adults being more active. Another pitfall is confusing overall daily energy expenditure, which includes activity, with basal metabolic rate itself. Keeping these concepts separate helps avoid incorrect assumptions.

Final Answer:
The statement that is not true about human metabolism is Younger people generally have a slower metabolism than adults.