Which layer of the earth is a solid and why?

The inner core is solid because of the high pressure and temperature!! Hope I could help :)

The crust is solid and this is because the crust was formed by magma that later was cooled causing it to form the earths crust

lysosomes contain a variety of enzymes, enabling the cell to break down various biomolecules it engulfs, including peptides, nucleic acids, carbohydrates, and lipids (lysosomal lipase). the enzymes responsible for this hydrolysis require an acidic environment for optimal activity. hope i !