Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

2. Cell Chemistry & Cell Components

Introduction to Biomolecules

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Introduction to Biomolecules

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Multiple Choice

Which substance comprises between 45% and 75% of the human body by weight?

Water

Protein

Fat

Carbohydrates

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Verified step by step guidance

Step 1: Begin by understanding the composition of the human body. The human body is primarily made up of water, proteins, fats, carbohydrates, and other substances. Water is the most abundant component.

Step 2: Recall that water is essential for various physiological processes, including temperature regulation, nutrient transport, and waste removal. It constitutes a significant percentage of body weight.

Step 3: Analyze the percentage range provided in the question (45% to 75%). This range is consistent with the proportion of water in the human body, which varies based on factors such as age, sex, and body composition.

Step 4: Compare the other options (protein, fat, carbohydrates). Proteins, fats, and carbohydrates are present in smaller proportions compared to water. Proteins make up about 15-20% of body weight, fats vary widely but are generally less than water, and carbohydrates are present in even smaller amounts.

Step 5: Conclude that the substance comprising between 45% and 75% of the human body by weight is water, based on its physiological importance and the percentage range provided.