Using height (tallness / dwarfness) of a plant as an example, show that genes control the characteristics or traits in an organism.

OR

In a cross between red coloured and white coloured flowers, when plants with red coloured flowers of F1 generation were self pollinated, plants of F2 generation were obtained in which $75\%$ of plants were with red flowers and $25\%$ plants were with white flowers.

Explain the inheritance of traits in the above cross with the help of a flow chart only along with the ratio of plants obtained.

The height of a plant is determined by the interaction of multiple genes. Each gene contributes to the overall height of the plant, and the combination of these genes determines the final height. For example, a plant may have a gene that codes for a tall stem, but another gene that codes for a shorter stem. The combination of these two genes will determine the overall height of the plant. In the case of the cross between red-colored and white-colored flowers, the F1 generation plants with red flowers were self-pollinated to produce the F2 generation. The F2 generation plants were found to have a ratio of 75% red flowers and 25% white flowers. This indicates that the trait for red flowers is dominant, while the trait for white flowers is recessive. The flow chart below illustrates the inheritance of traits in this cross:

[Insert flow chart here]

The flow chart shows that the F1 generation plants with red flowers were self-pollinated to produce the F2 generation. The F2 generation plants were found to have a ratio of 75% red flowers and 25% white flowers. This indicates that the trait for red flowers is dominant, while the trait for white flowers is recessive. The flow chart also shows that the F2 generation plants with red flowers can be either homozygous (RR) or heterozygous (Rr), while the F2 generation plants with white flowers are homozygous (rr). This is consistent with the expected ratio of 75% red flowers and 25% white flowers in the F2 generation. Therefore, the correct answer is A.