In a certain plant, yellow leaves are dominant and red leaves are recessive. A plant with genotype Yy and a plant with Yy are crossed. If they have four offspring, how many would you predict would have red leaves?

One offspring would have red leaves.

Explanation:

Given

Yellow leaves are dominant and red leaves are recessive

Let us assume that the trait of Yellow color of a leaf be represented by "Y"

and the trait of red color of a leaf be represented by "y"

When two parent of genotype "Yy" are crossed with each other, the following offsprings are produced as shown in the punnet square below

Y y

Y YY Yy

y Yy yy

Total four offpsrings are produced out of which only one has red leave as red color is a recessive trait and it will appear only when both the allele in a cell are of red color.

Thus, one offspring would have red leaves.