Question

Why did Mendel prevent his plants from self-pollinating? so they couldn't produce offspring to insure that each plant's offspring would remain identical to the parents to control the crossing of the traits to maintain a pure strain

Answer 1

The first option. So they​ couldn't produce offspring.
Mendel was cross pollinating the plants. While he was doing to that he found out about "The Principal Of Dominance" meaning some alleles are recessive while some are dominant.

Answer 2

Answer:

The correct answer is "to control the crossing of the traits to maintain a pure strain".

Explanation:

  Gregor Mendel is considered the father of genetics for his studies of inheritance in pea plants. Mendel studied how the pea plant's traits are transferred through generations by cross-pollination. However, in nature pea plants are usually reproduced by self-pollination at which the progeny is produced by a single plant. Mendel prevented his plants from self-pollinating to control the crossing of the traits to maintain a pure strain. By doing so, Mendel assured that the only reproducing method that he was studying was cross-pollination.

I hope this helped you, whatever your pronouns are.