The rate of appearance of new life forms is linked to their

Options

A. Acquired traits
B. Nonheritable characters
C. Life span
D. Cranial capacities

Answer

To solve the question regarding the rate of appearance of new life forms and its link to certain characteristics, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the relationship between the rate of appearance of new life forms and specific traits or characteristics. The options provided are acquired traits, non-heritable characters, life span, and cranial capacities.

2. **Analyze the Options**:
- **Acquired Traits**: These are traits that an organism develops during its lifetime and are not passed on to offspring. They do not contribute to the genetic variation necessary for new life forms to appear.
- **Non-Heritable Characters**: Similar to acquired traits, these characters do not have a genetic basis and therefore do not influence the appearance of new life forms.
- **Life Span**: This refers to the duration of an organism's life. Organisms with shorter life spans tend to reproduce more quickly and have more generations in a given time frame, leading to higher rates of variation and the potential for new species to emerge.
- **Cranial Capacities**: This refers to the size of the braincase and does not directly relate to the rate of appearance of new life forms.

3. **Link Life Span to Variation**: It is important to note that organisms with shorter life spans can undergo more rapid reproduction cycles. For example, microbes can multiply rapidly, leading to a high degree of variation in a short period, which can result in the emergence of new species. In contrast, organisms with longer life spans, like fish, have fewer generations in the same time frame, resulting in lower variation.

4. **Conclusion**: Based on the analysis, the correct answer is that the rate of appearance of new life forms is linked to their **life span**. This is because shorter life spans allow for more rapid reproduction and greater genetic variation, facilitating the emergence of new species.

### Final Answer:
The rate of appearance of new life forms is linked to their **life span**.

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