WGU D440 – Health and Wellness
Through Nutritional Science Exam
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf.
1. Which nutrient provides the body's primary source of energy
under normal conditions?
A. Protein
B. Carbohydrates
C. Vitamins
D. Minerals
Rationale: Carbohydrates are the body's preferred energy source
because they are readily converted to glucose, which fuels the brain,
nervous system, and muscles. Although fats provide more calories per
gram, carbohydrates are metabolized more efficiently for immediate
energy needs.
2. How many calories are provided by one gram of fat?
A. 4 kcal
B. 5 kcal
,C. 7 kcal
D. 9 kcal
Rationale: Fat provides 9 calories per gram, making it the most energy-
dense macronutrient. Carbohydrates and proteins each provide 4
calories per gram, while alcohol provides 7 calories per gram.
3. Which vitamin is primarily responsible for promoting calcium
absorption in the small intestine?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Rationale: Vitamin D increases intestinal absorption of calcium and
phosphorus, supporting bone mineralization and maintaining normal
serum calcium levels. Deficiency can lead to rickets in children and
osteomalacia in adults.
4. Which nutrient is the body's primary structural component for
building and repairing tissues?
A. Carbohydrates
B. Lipids
C. Protein
D. Fiber
Rationale: Proteins are composed of amino acids that support tissue
growth, repair, enzyme production, hormone synthesis, and immune
,function. Adequate protein intake is especially important during healing
and periods of growth.
5. Which mineral is most closely associated with oxygen transport in
the blood?
A. Calcium
B. Potassium
C. Iron
D. Magnesium
Rationale: Iron is a key component of hemoglobin, which carries oxygen
from the lungs to tissues. Iron deficiency commonly results in microcytic
anemia, fatigue, and decreased exercise tolerance.
6. Which food is considered a complete protein source?
A. Brown rice
B. Black beans
C. Eggs
D. Almonds
Rationale: Complete proteins contain all nine essential amino acids in
adequate amounts. Animal foods such as eggs, dairy, meat, poultry, and
fish are complete protein sources, while most plant proteins are
incomplete unless combined appropriately.
7. Dietary fiber primarily contributes to which health benefit?
, A. Increased blood glucose levels
B. Improved bowel function and reduced cholesterol
C. Increased sodium retention
D. Decreased satiety
Rationale: Soluble fiber helps lower LDL cholesterol and stabilize blood
glucose, while insoluble fiber promotes bowel regularity and prevents
constipation. Fiber also increases feelings of fullness, supporting weight
management.
8. Which nutrient is the body's major storage form of energy?
A. Protein
B. Glycogen
C. Fat
D. Glucose
Rationale: Fat stored in adipose tissue serves as the body's largest
energy reserve. Glycogen stores are relatively limited and provide only
short-term energy during fasting or physical activity.
9. Which organ is primarily responsible for producing bile that aids in
fat digestion?
A. Pancreas
B. Gallbladder
C. Liver
D. Stomach
Through Nutritional Science Exam
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf.
1. Which nutrient provides the body's primary source of energy
under normal conditions?
A. Protein
B. Carbohydrates
C. Vitamins
D. Minerals
Rationale: Carbohydrates are the body's preferred energy source
because they are readily converted to glucose, which fuels the brain,
nervous system, and muscles. Although fats provide more calories per
gram, carbohydrates are metabolized more efficiently for immediate
energy needs.
2. How many calories are provided by one gram of fat?
A. 4 kcal
B. 5 kcal
,C. 7 kcal
D. 9 kcal
Rationale: Fat provides 9 calories per gram, making it the most energy-
dense macronutrient. Carbohydrates and proteins each provide 4
calories per gram, while alcohol provides 7 calories per gram.
3. Which vitamin is primarily responsible for promoting calcium
absorption in the small intestine?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
Rationale: Vitamin D increases intestinal absorption of calcium and
phosphorus, supporting bone mineralization and maintaining normal
serum calcium levels. Deficiency can lead to rickets in children and
osteomalacia in adults.
4. Which nutrient is the body's primary structural component for
building and repairing tissues?
A. Carbohydrates
B. Lipids
C. Protein
D. Fiber
Rationale: Proteins are composed of amino acids that support tissue
growth, repair, enzyme production, hormone synthesis, and immune
,function. Adequate protein intake is especially important during healing
and periods of growth.
5. Which mineral is most closely associated with oxygen transport in
the blood?
A. Calcium
B. Potassium
C. Iron
D. Magnesium
Rationale: Iron is a key component of hemoglobin, which carries oxygen
from the lungs to tissues. Iron deficiency commonly results in microcytic
anemia, fatigue, and decreased exercise tolerance.
6. Which food is considered a complete protein source?
A. Brown rice
B. Black beans
C. Eggs
D. Almonds
Rationale: Complete proteins contain all nine essential amino acids in
adequate amounts. Animal foods such as eggs, dairy, meat, poultry, and
fish are complete protein sources, while most plant proteins are
incomplete unless combined appropriately.
7. Dietary fiber primarily contributes to which health benefit?
, A. Increased blood glucose levels
B. Improved bowel function and reduced cholesterol
C. Increased sodium retention
D. Decreased satiety
Rationale: Soluble fiber helps lower LDL cholesterol and stabilize blood
glucose, while insoluble fiber promotes bowel regularity and prevents
constipation. Fiber also increases feelings of fullness, supporting weight
management.
8. Which nutrient is the body's major storage form of energy?
A. Protein
B. Glycogen
C. Fat
D. Glucose
Rationale: Fat stored in adipose tissue serves as the body's largest
energy reserve. Glycogen stores are relatively limited and provide only
short-term energy during fasting or physical activity.
9. Which organ is primarily responsible for producing bile that aids in
fat digestion?
A. Pancreas
B. Gallbladder
C. Liver
D. Stomach
