1. in pea plants, tall (t) is dominant to dwarf (t). show the cross
between a heterozygous tall and a dwarf plant. what are the
expected phenotypes and in what proportion?

Tt - 2/4 = 1/2 or 50%            Heterozygous TALL

tt - 2/4 = 1/2 or 50%             Homozygous Dwarf

Explanation:

So let's make a Punnett for this so you can see what the outcome is yourself:

Tall is dominant - T

Dwarf is recessive - t

Heterozygous means that they have one of each allele. The genotype of one parent would be then Tt.

***It is heterozygous tall because Tall is a dominant trait so if it is accompanied by the recessive trait dwarf, then the Tall allele would mask it.

The other parent is a dwarf plant. The genotype would then be tt.

*** Now for a recessive trait to appear, it should not have a dominant trait mixed with it, which could mask it. The result then is homozygous recessive or homozygous Dwarf.

So now that we know the genotypes of the parent plants, we can put it into a Punnet:

    t      t

T  Tt   Tt

t   tt    tt

As you can see, out of the 4 outcomes we have:

Tt - 2/4 = 1/2 or 50%            Heterozygous TALL

tt - 2/4 = 1/2 or 50%             Homozygous Dwarf

B.Gymnoperms produce male cones and female cones, and the pollen from a male cone fertilizes the egg inside a female cone.