What does 'R' represent in the given equation for productivity in an ecosystem ?
`GPP-R=NPP`

Explanation

To understand what 'R' represents in the equation \( GPP - R = NPP \), we can break down the components of the equation step by step.

### Step-by-Step Solution:

1. **Understand the Terms**:
- **GPP (Gross Primary Productivity)**: This is the total amount of biomass produced by autotrophic organisms (like green plants) through photosynthesis in a given area over a specific time period.
- **NPP (Net Primary Productivity)**: This is the amount of biomass that remains after the autotrophs have used some of the energy for their own metabolic processes. It represents the energy available to the next trophic level in the food chain.

...