What happens to a red blood cell place in a glass of water?

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Check all that apply diatoms are marine algae that have a shell made of silica, what are some of the uses of the silica shell after the diatoms die? 1.the shells make up the diatomaceous earth used in filters 2.it can be used as an ingredient in abrasives 3.they are used in food products 4.the shells can be used in some insulating materials

What would most likely happen to a unicellular organism if it was exposed to a hypotonic solution for an extended period of time?