Insertion mutation takes the T out and replaces it with an A.
A codon is a sequence of three nucleotides in DNA or RNA that codes for either a particular amino acid or tells the cellular machinery to start or stop using the code. It isn't located anywhere specific.
number 2
number 2 because the colour doesnt matter
Plant A would have one allele from each parent, so the leaf color will be the dominant one.
Plant B would have a more complex percentage for traits. And it'll probably "cancel-out" some alleles only showing the info given in one of them.
Hope it helped,
BioTeacher101