Keystone species deserve protection because these
(a) are capable of surviving in harsh environmental conditions
(b) indicate presence of certain minerals in the soil
(c) have become rare due to overexploitation
(d) play an important role in supporting other species

Options

A. are capable of surviving in harsh environmental conditions
B. indicate presence of certain minerals in the soil
C. have become rare due to overexploitation
D. play an important role in supporting other species.

Explanation

To determine why keystone species deserve protection, we can analyze each option provided in the question:

1. **Understanding Keystone Species**: A keystone species is one that has a disproportionately large impact on its environment relative to its abundance. These species play a crucial role in maintaining the structure of an ecological community.

2. **Analyzing the Options**:
- **(a) are capable of surviving in harsh environmental conditions**: While some keystone species may indeed survive in harsh conditions, this characteristic alone does not justify their protection. This option does not directly relate to the ecological role of keystone species.

- **(b) indicate presence of certain minerals in the soil**: This option refers to bioindicators, which are different from keystone species. Keystone species do not primarily serve as indicators of soil minerals, so this option is not correct.

- **(c) have become rare due to overexploitation**: Although some keystone species may be rare due to overexploitation, the reason for their protection is not solely based on their rarity. This option does not capture the essence of why keystone species are critical to ecosystems.

- **(d) play an important role in supporting other species**: This option accurately reflects the role of keystone species. They help maintain the balance of ecosystems and support a variety of other species by providing essential functions such as predation, habitat structure, and resource availability.

3. **Conclusion**: Based on the analysis, the correct answer is (d) play an important role in supporting other species. Keystone species are vital for the health and stability of their ecosystems, and their protection is essential to maintain biodiversity.