A lizard with a striped tail and a normal head is crossed with one having a normal tail and a spotted head. All the F 1 progeny are normal (no stripes or spots). What progeny are expected from a cross of the F 1 progeny

9 normal : 3 striped : 3 spotted: 1 striped and spotted.

Explanation:

The F1 progeny contains no spots or stripes and are considered as normal, it means normal tail and normal head are dominant on their alternative traits. So, it means that the F1 progeny are heterozygous in nature for both of the traits.

The cross between 2 F1 progeny is dihybrid cross of lizards (heterozygous) which will produce offspring in 9:3:3:1 ratio, where 9 are normal, 3 striped which are dominant in the one character, 3 spotted which are dominant in other, and 1 will be stripped and spotted which is recessive in nature.