What do cells do when they are to closely packed together??

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

Hedgerows have created a new ecosystem within britain’s a. farms b. cities c. forests d. industrial areas

Me with biology endocrine system crossword also image left i need with hw