If two orange heliodors have a child, what is the probability their child would be red?

25% or 1/4

Explanation:

The gene for colour in Heliodors is controlled by two contrasting alleles that codes for Red (R) and Yellow (Y) colours. However, these two alleles exhibit incomplete dominance, which is a phenomenon whereby a combination of both alleles gives rise to a third intermediate phenotype that is a blending of the other two parental phenotypes. In this case, both colours gives rise to a heterozygous Orange coloration (RY) in Heliodors.

However, if two orange Heliodors (RY) are crossed, four possible offsprings will be produced with the genotypes: RR, RY, RY, YY. This shows a phenotypic ratio of 1 red: 2orange: 1yellow. Hence, the probability of having a child with red coloration is 1 out of 4 possible offsprings i.e. 1/4.

Expressing this in percentage, we have 1/4 × 100 = 25%.