Which of the following changes for man in the course of evolution is probably useless?

Options

A. Development of cranial capacity
B. Development of opposable thumb
C. Development of being erect
D. Loss of tail

Answer

To determine which of the evolutionary changes in humans is probably useless, we will evaluate each option provided:

1. **Development of cranial capacity**:
- This refers to the increase in the size of the skull to accommodate a larger brain. A larger brain is associated with higher intelligence and cognitive abilities, which are advantageous for survival and adaptation. Therefore, this change is useful.

2. **Development of opposable thumb**:
- The opposable thumb allows for a better grip and manipulation of objects, which is crucial for tool use and various tasks. This adaptation has significantly contributed to human success and survival. Thus, this change is also useful.

3. **Development of being erect**:
- The ability to walk upright (bipedalism) has allowed humans to cover long distances efficiently, free up the hands for tool use, and improve visibility in the environment. This adaptation has been beneficial for survival, making it a useful change.

4. **Loss of tail**:
- While many primates have tails that help with balance and mobility, humans do not have a functional tail. The loss of the tail does not seem to provide any significant advantage in human evolution. Therefore, this change is likely to be considered useless.

Based on the evaluation of these options, the change that is probably useless in the course of human evolution is the **loss of tail**.

### Summary of the Solution:
The useless change for man in the course of evolution is the **loss of tail**.