Crossword
 
1
2
3 4
5
6
7
Across:
2 Population
3 A natural group of animals with hard shells.
5 Relating to the bottom of the sea
7 Movement of animals from place to place
Down:
1 A way of hearing sounds from far away
4 Situated at or near the head
5 When a dolphin leaps completely out of water
6 Group of cetaceans