In which plant are both autogamy and geitonogamy prevented?

In papaya, both autogamy (self-fertilization) and geitonogamy (fertilization occurring between flowers of the same plant) are prevented due to its dioecious nature. This means that male and female flowers are borne on separate plants. Consequently, a male papaya plant only produces male flowers that can’t fertilize the female flowers on others, thereby ensuring that fertilization must occur between different plants, which helps in promoting genetic diversity.

This reproductive strategy is advantageous for papaya as it encourages cross-pollination by attracting pollinators, which can lead to greater vigor and resilience in offspring. In contrast, tomato, peach, and mango plants can potentially self-pollinate or engage in geitonogamy since they can either have perfect flowers or the capacity for flowers of the same plant to be involved in the fertilization process. Therefore, papaya distinctly prevents both forms of self-fertilization, making it the correct choice.