In a cross between two heterozygous individuals (eg. rr x rr), the expected phenotypic ratio of the offspring would be

The correct answer would be 3:1.

The genotype of both the parent is given as heterozygous dominant, that is, Rr.  

They both form two types of gametes, one gamete would contain R and another gamete would contain r.

The cross would result in the production of offspring with three possible types of genotypes RR, Rr, and rr in the ratio 1:2:1.

Thus, three out of the four offspring have the probability of having dominant phenotype.

Therefore, the phenotype ratio would be 3 (dominant phenotype): 1 (recessive phenotype).

one would be wind another would be water density