Answer:a. A cataract is a clouding of the lens. Some cataracts are congenital, but most are due to age-related hardening and thickening of the lens, diabetes mellitus, or exposure to UV rays over time. The lens can be removed and replaced
with an artificial lens.
Explanation:
The zygote, a single cell, implants its self to the uterine wall and it developes into an embyro which is a cluster of cells.
A seems most probable.
Oceans are also deeper and larger then Seas.