An organ system is made up of a number ___________which are made of ___________

Options

A. organs, tissue
B. organelle, tissue
C. organism, tissue
D. tissue, organ

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the composition of an organ system. Specifically, it wants to know what an organ system is made of and what those components are made of.

2. **Identifying the Components**: An organ system is made up of multiple organs. For example, the digestive system includes organs like the stomach, intestines, and liver.

3. **Understanding the Structure of Organs**: Each organ is made up of tissues. Tissues are groups of similar cells that work together to perform a specific function. For instance, the stomach has muscle tissue, epithelial tissue, and connective tissue.

4. **Finalizing the Answer**: Therefore, we can conclude that an organ system is made up of a number of **organs**, which are made of **tissues**.

5. **Complete Answer**: An organ system is made up of a number **of organs** which are made of **tissues**.

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