I cant really answer all because Im not smart XD sorry.
1. The Stamen is the 'male' part of the flower which holds the pollen (sperms for human)
The Pistil then is the 'female' part where the pollen go.
2. Pollen grains go to the ovules and thus needs to be 'more' so there is more chances of it going to deifferent places, while the ovum is few because it stays there in the flower.