
The designation Rr for a pea-plant's peas shows that the plant is a <u>true-breeding plant</u>.
Your question isn't the most clear, but I think your answer is rocks, or more specifically phosphorous rich rocks because the phosphorous will mix with the sediments on the river's/lake's ground forming phosphorous rich rocks.
That means that It'll become a phosphate mineral and later become phosphorous again when the minerals weather.
Hope it helped,
BioTeacher101
The answer is C) Increase genetic variation and breed plants to contain the wild variety.