Secondary productivity is rate of formation of new organic matter by:

Options

A. Consumer
B. Decomposer
C. Producer
D. Parasite

Answer

To answer the question "Secondary productivity is the rate of formation of new organic matter by:", we will analyze the options provided and understand the concept of secondary productivity.

### Step-by-Step Solution:

1. **Understanding Productivity**:
- Productivity in ecology refers to the rate at which energy is converted into organic substances by living organisms. It is divided into two categories: primary productivity and secondary productivity.

2. **Primary Productivity**:
- Primary productivity is the rate at which producers (like plants) convert sunlight into organic matter through photosynthesis. This organic matter serves as the food source for other organisms.

3. **Defining Secondary Productivity**:
- Secondary productivity refers to the generation of new organic matter by consumers. These are organisms that obtain their energy by consuming other organisms (either producers or other consumers).

4. **Role of Consumers**:
- Consumers include herbivores, carnivores, and omnivores. They take the organic matter produced by primary producers and convert it into their own organic matter. For example, when a herbivore eats plants, it converts the plant's organic matter into its own body mass.

5. **Evaluating the Options**:
- **Consumers**: Correct. They are responsible for secondary productivity as they form new organic matter by consuming primary producers.
- **Decomposers**: Incorrect. They break down dead organic matter into simpler substances but do not create new organic matter.
- **Producers**: Incorrect. They are involved in primary productivity, not secondary.
- **Parasites**: Incorrect. While they are a type of consumer, they do not represent the broader category of consumers responsible for secondary productivity.

6. **Conclusion**:
- The correct answer is **Consumers**. They are the organisms that contribute to secondary productivity by forming new organic matter from the organic matter produced by primary producers.

### Final Answer:
**Consumers**