问题
单项选择题
What is especially unique about sea horse().
A. They make attractive ornaments in seashell shops.
B. They can be kept as pets in home aquariums.
C. They have much smaller scales than most fish.
D. Only the male sea horse becomes pregnant.
答案
参考答案：D
解析：
[难点] 该题涉及到最后一段。选项a、b、c均不符合原文内容，d为正确选项。