In pea plants, purple flowers are dominant over white flowers. the phenotype ratio of purple to white flowers in a population of five plants is 4: 1. how many plants have white flowers?
1
2
4
5

in some lizard species, a short tail is recessive and a long tail is dominant. according to the principle of dominance:
a lizard with a tt genotype will have a short tail
a lizard with a tt genotype will have a long tail
a lizard with a tt genotype will have a short tail
a lizard with a tt genotype will have a short tail

1. 1
Since the ratio is purple flowers to white flowers, and the ratio is 4:1 out of 5 plants, there is 1 white flower. Remember that, in a ratio, the first number is the first one mentioned, and the second number is the second one mentioned.

2. A lizard with a tt genotype with have a short tail
Since the short tail is recessive, it can be represented with a lowercase letter (t), and since the long tail is dominant, it can be represented with a capital letter (T). Because the long tail gene is dominant, if even one capital T is present in a genotype, the lizard will have a long tail. You can label the different kinds of genotypes if it helps.

TT - long tail, since both genes are for a long tail
Tt - long tail, since one gene is for a long tail, and the long tail is dominant
tt - short tail, since both genes are for a short tail

Hope this helps!