Q.What is sap?
A.A juice.

Q.How can the sap make the buds larger?
A.It comes out of the root, and goes up the stem.

Q.What next?
A.Through the branches into the buds.

Q.What do the buds produce?
A.Some buds produce leaves, some blossoms, and some a shoot.

Q.What do you mean by a shoot?
A.
A young branch, which is green at first, but becomes hard by age.