Question

Which part of meiosis, meiosis 1, or meiosis 2 is responsible for the reducing of the chromosomes by half?

Answer 1

In Meiosis I, the chromosomes replicate so when the cell divides you have the same number of chromosomes as the original cell. But then the cell divides again (Meiosis II) without chromosome replication, so each daughter cell has half of the number of chromosomes as the parent cell.
So, Meiosis II is responsible for the reducing of chromosomes by half.