How do an eggshell and a membrane maintain homeostasis for a developing chicken? help pls

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

In the reaction between a crushed antacid tablet and vinegar what gas is emitted

Miner's coal distributors does not mine coal itself, nor does it even store or handle the coal. instead, miner's solicits orders for low sulfur coal from other firms, then purchases the required amount from suppliers and directs them to ship the coal to its customers. what is miner's