The most abundant chemical in living organisms could be

Options

A. protein
B. water
C. sugar
D. nucleic acid

Answer

To determine the most abundant chemical in living organisms, we can analyze the options provided:

1. **Protein**:
- Proteins are essential biomolecules that make up a significant portion of the body. In humans, proteins account for approximately 20% of body mass. While they are crucial for various functions, they are not the most abundant chemical.

2. **Water**:
- Water is a vital component of living organisms. In humans, water constitutes about 60% to 70% of body weight. It plays a critical role in cellular processes and can easily pass through cell membranes without requiring active transport. This high percentage indicates that water is indeed the most abundant chemical in living organisms.

3. **Sugar**:
- Sugars (or carbohydrates) are present in the body but in much smaller quantities. For instance, in a human body with approximately 5 liters of blood, there are only about 4 grams of sugar. This amount is negligible compared to the percentages of proteins and water.

4. **Nucleic Acids**:
- Nucleic acids, which include DNA and RNA, are also present in living organisms but in lesser amounts compared to water. They are crucial for genetic information but do not constitute a large percentage of body mass.

Based on this analysis, the most abundant chemical in living organisms is **water**, which makes up about 60% to 70% of the body.

**Final Answer**: The most abundant chemical in living organisms is **water**.