单项选择题

According to the passage, student researchers may have to change their research projects because

A．their budgets are too high
B．their original questions are too broad
C．their teachers do not give adequate advice
D．their time is very limited
<上一题 目录 下一题>
热门 试题

单项选择题
Warm-blooded animals maintain a steady temperature by ______.
A．storing heat in their body cells
B．regulating the amount of heat produced
C．regulating the amount of heat given off
D．constantly replacing lost surface heart
单项选择题
An animal weighing less than 2.5 grams would starve because it would not be able to ______.
A．get enough oxygen
B．maintain its body temperature
C．bum its food fast enough
D．eat fast enough to supply fuel
相关试题