Final answer:
The first major activity of fertilization is contact and recognition between sperm and egg. It involves the acrosomal reaction where enzymes degrade the egg's protective layer, allowing sperm to penetrate and eventually fuse their genetic material. So the correcct option is C.
Step-by-step explanation:
The first major activity of fertilization is c) contact and recognition between sperm and egg. This is the initial step before any other actions, like the fusion of genetic material, can occur. Specifically, when a sperm encounters an egg, the sperm's acrosome (a specialized structure at the tip of the sperm head) releases enzymes to degrade the glycoprotein matrix that makes up the zona pellucida, the protective layer of the egg. This process is known as the acrosomal reaction, allowing the sperm to penetrate the egg's surface and facilitating the eventual fusion of the sperm and egg plasma membranes. Following this, the sperm nucleus is transferred into the ovum, leading towards the combination of their respective haploid genomes to form a diploid zygote.