Explanation:

- Ornithology:

- The scientific study of birds.

- It involves observing avian behavior, ecology, and conservation.

- Correct Answer: The study of birds.

- Ichthyology:

- The study of fish.

- It covers a wide range of fish species and aquatic environments.

- Gerontology:

- The study of aging and the problems associated with it.

- Focuses on the social, psychological, and biological aspects of aging.

- Pomology:

- The science of growing fruit.

- Concentrates on fruit crops, including apples and berries.