Which cross will yield four phenotypes in the 1: 1: 1: 1 ratio

The answer is RrYy x rryy.

It is known that the in dihybrid cross (a cross between two different traits), the phenotypic ratio between the offspring in the F2 generation is 9:3:3:1. To get phenotypes in ratio 1:1:1:1, there must be a cross between heterozygote for both traits and recessive homozygote for both traits. This can be concluded if these two traits are analyzed separately:
Parents:       Rr    x    rr
Offspring: Rr    Rr   rr    rr
So, the ratio is 2:2 or 1:1.
The same ratio is for cros Yy x yy.
Thus, the cross between RrYy and rryy will yield four phenotypes in the 1:1:1:1 ratio.
In the attached photo, 1/4 of the offspring are RrYy, 1/4 are Rryy, 1/4 are rrYy, and 1/4 rryy. The ratio is 1/4:1/4:1/4:1/4, which is the same as 1:1:1:1.

Fungi is were it belongs

Mars and earth have quite a few things in common. both are  terrestrial planets, both are located within the sun’s  habitable zone, both have  polar ice caps, similarly  tilted axes, and similar  variations in temperature. and according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that mars once had a  dense atmosphere  and was covered with  warm, flowing water.