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:
<span>The answer is: Strata</span>
Answer:
Red blood cells transport oxygen around the body. They are specialised to carry oxygen because they: contain large quantities of a protein called haemoglobin , which can bind oxygen. don't have a nucleus, so there is more room for haemoglobin.
Explanation:
Stone tools we’re first used around 3,300 BCE
