Which one of the following is not a characteristic of animals?

Options

A. Heterotrophic
B. Diplontic life cycle
C. Have contracting fibres
D. Single cells or colonial

Explanation

To determine which of the following is not a characteristic of animals, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Characteristics of Animals**:
- Animals are multicellular organisms.
- They are heterotrophic, meaning they obtain their food by consuming other organisms.
- Animals have a diploid life cycle, which means their body cells contain two sets of chromosomes.
- Animals possess contracting fibers in their muscles, which allow for movement.

2. **Evaluate Each Option**:
- **Heterotrophic**: This is a characteristic of animals. They cannot produce their own food and rely on other organisms for nutrition.
- **Diploid Life Cycle**: This is also true for animals. Most animals have a diploid stage in their life cycle.
- **Contracting Fibers**: Animals have muscle fibers that contract, enabling movement. This is a true characteristic.
- **Single-Celled**: This is not true for animals. While some organisms (like bacteria and protozoa) are single-celled, animals are primarily multicellular.

3. **Identify the Incorrect Characteristic**:
- Among the options, "single-celled" is the only statement that does not describe a characteristic of animals. Therefore, this is the correct answer.

### Conclusion:
The characteristic that is not true for animals is that they are "single-celled." Animals are multicellular organisms.

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