Question

In a classic experiment using pea shape, Mendel conducted two separate genetic crosses. In the first cross the parent plants were “true breeding” for pea shape; one had round peas ( R ) and the other had wrinkled (r). The first cross produced a filial 1 generation of all round peas. In the second cross, Mendel bred plants from the filial 1 generation. This cross produced different results. Out of approximately 1000 plants, about 75% were round and 25% were wrinkled. From these experiments, Mendel developed four hypotheses. They include all but ___________. A. One heritable factor may be dominant and mask the other factor. B. Any organism that "shows" a heritable factor must be homozygous.
Eliminate C. An organism has two "heritable factors", now called genes, one from each parent.
D. sperm or egg carries only one heritable factor for each trait in the offspring.

Answer 1

B. Any organism that "shows" a heritable factor must be homozygous. 

Let's go through all choices:
A. TRUE! One heritable factor may be dominant and mask the other factor called recessive.
B. FALSE! Heterozygous organism can "show" a trait as well. If there is one dominant and one recessive form, a dominant form will mask it and dominant trait will be expressed. 
C. TRUE! An organism gets one form of the gene from the mother, and one from the father.
D. TRUE! That's why sperm or egg are called haploid.

Answer 2

Answer:

A) one heritable factor may be dominant and mask the other factor

Explanation:

any organism that shows a heritable factor must be homozygous.  Mendel did not know  or use terms such as genes, alleles, or homozygous versus heterozygous.