State two disadvantages of cross pollination.

Explanation

**Step-by-Step Solution:**

1. **Definition of Cross-Pollination**: Cross-pollination is the transfer of pollen from the male anther of one flower to the female stigma of another flower, typically on a different plant. This process promotes genetic diversity in plants.

2. **Disadvantage 1 - Wastage of Pollen**: One major disadvantage of cross-pollination is that it requires the production of a large quantity of pollen to increase the chances of successful pollination. However, this can lead to significant wastage of pollen, as not all pollen grains will successfully reach a compatible stigma.

3. **Disadvantage 2 - Uncertainty of Pollination**: Another disadvantage is that cross-pollination is not always guaranteed. It relies on external pollinating agents such as wind, insects, or water to transfer pollen. If these agents are not available or if they do not effectively carry the pollen to the right plant, successful pollination may not occur.

...