Reduce carbon dioxide emissions, pollution, and deforestation
reuse materials rather than throwing them away and needing to create more
recycle materials like metals, paper, and plastics
replace non-biodegradable materials with biodegradable
The answer is guard cells.
Guard cells are cells surrounding each stoma. They help regulate the rate of transpiration by opening and closing the stomata. They are specialized cells in the epidermis of leaves, stems and other organs that are used to control gas exchange. They are produced in pairs with a gap between them that forms a stomatal pore (stoma).
A) Stone
They used materials they were available to them which was majorly limestone which is a type of stone.
