Which is the first step of respiration ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Respiration**: Respiration is a biochemical process that cells use to convert glucose into energy. It involves several steps, which can be categorized into cellular respiration and external respiration.

2. **Identifying the First Step**: The first step of cellular respiration is known as glycolysis. This is where glucose, a six-carbon sugar, is broken down into two three-carbon molecules called pyruvic acid.

3. **Location of Glycolysis**: Glycolysis occurs in the cytoplasm of the cell. This is significant because it means that glycolysis can take place in both aerobic (with oxygen) and anaerobic (without oxygen) organisms.

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