单项选择题
A．Man is more colour-conscious than the honey-bee. B．The honey-bee is blind to red. C．The honey-bee can see far more colours than man. D．Man is sensitive to the ultra-violet.
A．All senses have their limitations. B．Insects are more sensitive to colours than man. C．Man has not fully utilized all his senses. D．Man is not as good as animals in learning about the environment.
A．skins that are quick to feel and respond B．skins that are delicate C．skins that are completely dry D．skins that are sticky or slippery