Punnet squares are a useful tool for predicting what the offspring will look like when mating plants or animals. Reginald Crundall Punnett, a mathematician, came up with these in 1905, long after Mendel's experiments. Let's take a look at how Punnet squares work using the yellow and green peas example from im not sure about the tree by three thing but maybe this will help :)
Explanation:
The small number behind each element symbol designates the number of atoms of each element in a chemical formula. If there is no number, it is assumed there is only one of those elements. A large number designates how many units there are of that compound.
The last one
sorry if it’s wrong!!