Which fact is not observable in protobionts?

Options

A. They exhibit simple metabolism
B. They are colloidal clusters of macromolecules
C. They can grow in size by absorbing surrounding matter
D. They can reproduce

Answer

To determine which fact is not observable in protobionts, let's analyze each of the four statements provided:

1. **They exhibit simple metabolism.**
- Protobionts are believed to have some form of simple metabolism. They are capable of chemical reactions that can be considered metabolic processes, even if they are not as complex as those seen in modern cells.

2. **They are colloidal clusters of macromolecules.**
- This statement is accurate. Protobionts are indeed considered to be colloidal clusters of macromolecules, such as lipids, nucleic acids (DNA or RNA), and polysaccharides, which form the basis of their structure.

3. **They can grow in size by absorbing surrounding matter.**
- This is also true. Protobionts can grow by absorbing substances from their environment, similar to how living cells can take in nutrients and expand.

4. **They can reproduce.**
- This statement is the most contentious. While protobionts may exhibit some form of replication or self-replication, they do not reproduce in the same way that living organisms do. True reproduction involves complex processes like cell division, which protobionts do not perform.

### Conclusion:
The fact that is **not observable in protobionts** is that **they can reproduce** in the same manner as living organisms.