What type of lenses were used for the first microscopes?

Here is some background information...

Explanation:

Leeuwenhoek (1633-1723) used melted glass balls to form lenses for apparently crude simple microscopes that nevertheless magnified up to 275 times! Modern tests have concluded that he could have achieved a resolution of two micrometres.

one characteristic that is shared by all is a soft body. many

of these invertebrate animals also have an outer shell to protect their

body. oysters, clams, snails, and mussels are all mollusks. so are octopuses, squids, and slugs. mollusks live on land and in freshwater.