Final answer:
Gametes can be brought together through random fertilization and physical union.
Step-by-step explanation:
In sexual reproduction, two gametes can be brought together through two basic ways: random fertilization and physical union.
Random fertilization is the process where two gametes unite by chance, resulting in genetic variation in offspring. It occurs because there are millions of possible gametes, and which ones come together is a matter of chance.
Physical union refers to the physical act of bringing the two gametes in close proximity to each other. This can happen through various mechanisms, depending on the species. For example, in marine animals and amphibians, the male releases sperm into the water near the female's unfertilized eggs. In flowers, pollen is dispersed through the air and carried to another flower, where it comes in contact with the ovum.