USA Biology Olympiad (USABO) Practice Exam

Which of the following components is essential for the process of fertilization?

1. Gametes.

2. Phloem.

3. Chloroplasts.

4. Roots.

The correct answer is: Gametes.

Gametes are essential for the process of fertilization because they are the reproductive cells that combine to form a new organism. In animals, sperm and egg cells are the male and female gametes, respectively. During fertilization, the sperm successfully merges with the egg, resulting in the formation of a zygote, which is the first stage of development for a new organism. This process is fundamental to sexual reproduction, allowing for genetic diversity through the combination of genetic materials from two parents. In contrast, other components such as phloem, chloroplasts, and roots play different roles in plant biology. Phloem is involved in the transport of nutrients and food throughout the plant, chloroplasts are responsible for photosynthesis, converting light energy into chemical energy, and roots anchor the plant and absorb water and minerals from the soil. None of these components are directly involved in the fertilization process itself.