How are eggs adapted for fertilisation?

Eggs are adapted for fertilization through several key features. They possess a protective outer layer called the vitelline membrane, which helps to safeguard the egg and also facilitates the entry of sperm. Additionally, eggs are often larger and contain nutrient-rich yolk, providing the necessary resources for the developing embryo post-fertilization. The chemical composition of the egg's surface can also change after a sperm penetrates, preventing multiple sperm from fertilizing the same egg.