Question

A plant with white flowers was crossed with a plant with yellow flowers.

Fifteen of the offspring had white flowers, and five had yellow flowers. What
conclusion can you draw?
A. The offspring were pure-breeding.
B. The allele for white flowers is dominant.
C. The allele for yellow flowers is dominant.
D. The parent plants were pure-breeding.

Answer 1

B. The allele for white flowers is dominant.

Explanation:
Since it was crossed remember that most of the offspring have the characteristics of the parent with the dominant allele and since most offsprings came out white, well then white is the dominant allele

Answer 2

The conclusion that can be drawn from the given information is that the allele for white flowers is dominant.

Step-by-step explanation:

The offspring of the cross inherited one allele from each parent, and the ratio of 15:5 suggests a 3:1 ratio of white to yellow flowers.
If yellow were dominant, we would expect the ratio to be 1:2:1 (YY:Yy:yy), as both parents would have to be heterozygous (Yy) to produce yellow offspring.
Therefore, we can conclude that the plant with white flowers must have been homozygous dominant (WW) and the plant with yellow flowers must have been homozygous recessive (yy), resulting in all the offspring being heterozygous (Ww) for the white flower allele.