S1 - Self pollination can take place only in bisexual flowers.

S2 - Cross pollination can take place only in Unisexual flowers.

Correct Option: S1 is true and S2 is false

Step-by-Step Explanation:

1. Analysis of Statement S1: "Self pollination can take place only in bisexual flowers."

Self-pollination involves the transfer of pollen grains from the anther to the stigma of the same flower or another flower on the same plant. For self-pollination to occur within a single flower (autogamy), the flower must contain both male (stamen) and female (carpel/pistil) reproductive organs. Flowers containing both male and female structures are called bisexual flowers. Unisexual flowers contain only one of the reproductive structures (either stamen or carpel), so a single unisexual flower cannot undergo autogamy. Therefore, statement S1 is true.

2. Analysis of Statement S2: "Cross pollination can take place only in Unisexual flowers."

Cross-pollination (xenogamy) is the transfer of pollen grains from the anther of a flower on one plant to the stigma of a flower on another plant of the same species. While unisexual flowers must rely on cross-pollination (or geitonogamy) to reproduce, bisexual flowers can also undergo cross-pollination through mechanisms like dichogamy (differing maturity times of male and female parts) or self-incompatibility to prevent self-fertilization. Therefore, cross-pollination is not restricted exclusively to unisexual flowers; it occurs in bisexual flowers as well. Thus, statement S2 is false.

Conclusion:

Statement S1 is true and Statement S2 is false.