What did mendel's cross-pollination of pea plants prove?

a. each parent only passes on one-half of its hereditary factors to the offspring.

b. it takes four generations of offspring to determine the parents' factors.

c. there is no such thing as a true-breeding plant; they all have hidden factors.

d. inherited factors combine in offspring to make entirely new characteristics.

The correct answer would be A. Each parent only passes on one-half of its hereditary factors to the offspring.

It can be correctly explained with the help of the law of segregation.  

It states that the alleles of each gene get segregated from each other and each gamete produced by a parent would contain only one out of two alleles of a gene.

For example, if the genotype of a parent is Tt, then the gamete would contain either T or t.

Thus, each parent only contributes half of its heredity factors in the form of gametes.

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).