Mark Krofssik, age 9, of Monroe, Conn.,for his question:

HOW DOES A LOBSTER BREATHE?

The lobster cannot breathe air to get his oxygen, as we do. Instead, he takes his oxygen from the water and for this he does not need a nose and a pair of lungs. He needs gills to take dissolved oxygen and return used carbon dioxide to the salty sea. There are 40 small feathery gills, 20 on each side of hisbody, under his shell.

The sea water comes through cracks in the shell, and the gills take dissolved oxygen as it flows around them. As it exits through another crack, the water carries away used carbon dioxide.