[解析]
(1)A.细节理解题.根据文章第一段的句子"How did the sea horse get its name?It's not hard to guess.The top half of this fish looks like a small horse"可知海马名字的由来是因为它的头的形状.所以选A.
(2)B.细节理解题.根据第二段的句子"They keep safe from other fish by hiding in plants and grasses that grow under the sea."可知海马安全地躲避其他鱼类的方法是躲在植物和草中.所以选B.
(3)A.细节理解题.根据第三段的句子"The male carries the eggs in its pouch for about three weeks until they hatch."可知雌海马将海马的蛋放在雄海马的袋子里面,所以选A.
(4)C.细节理解题.根据文章最后一段的句子"Some places where sea horses once lived have been filled in to make new land.."可知海马的数量在减少因为它们生活的地方被破坏了,所以选C.