How can 2 plants that look the same on the outside produce offspring that look different from them?

They are both heterozygous therefore have a dominant gene (B) showing but have a recessive allele (b).

If Bb and Bb have offspring, they can have outcomes: BB, Bb or bb.
The offspring bb will have a different looking offspring.
Eg.
B: Brown eyes
b: Blue eyes

BB: Brown eyes (homozygous dominant)
Bb: Brown eyes (heterozygous)
bb: Blue eyes (homozygous recessive)

Blue eyes are the recessive gene and will not show unless both alleles are recessive.

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom. 

(no3)⁻n has oxidation number x,o has oxidation number -2.(x*1 -2*3) charge of the nitrate ion, and we know that charge of the nitrate ion =-1.so,(x*1 -2*3) =-1x-6=-1x=+5answer a. +5.