It is dead and must be discarded (unless it closes up quickly when tapped). Do not cook open clams, it is a health hazard.
If a clam does not open when cooked, that usually means the clam was dead before cooking. Do not eat clams that won't open when cooked. Make sure that the clams have plenty of space to open during the cook. Sometimes the weight on top will prevent opening.
I am not sure how to get a clam to open naturally. The way I have known to open a clam is by hand.
YES
You have to go underwater which is left to Aphrodite and you have to find a clam. It opens and closes. Try to get the pearl (which is inside the clam) when the clam is open.
the mussel of the clam keeps the shell together. But they can open it if the want.
You can tell if a clam is alive by observing if its shell is tightly closed or slightly open. If the clam is alive, it will try to close its shell tight when handled. A dead clam will have a gaping, gaping, or broken shell.
Open
If it doesn't open when you steam it.
On the beach
you get the pin that is by the clam
An open circulatory system.
the adductor muscles