Which is the longest cell in the human??​

Can someone me with questions 12 and 13 plz.

This drawing shows a human body system. what is the primary function of this body system?

Solutions of sodium carbonate and silver nitrate react to form solid silver carbonate and a solution of sodium nitrate. a solution containing 3.50 g of sodium carbonate is mixed with one containing 5.00 g of silver nitrate. how many grams of sodium carbonate, silver nitrate, silver carbonate, and sodium nitrate are present after the reaction is complete?