In the author's opinion, visual and spatial abilities are good for ______.

A．Because they have no visual spatial skills.
B．Because they are only good at language and verbal reasoning.
C．Because they are less likely to see their charming or interesting aspects.
D．Because they rarely use machines such as cars, titles, computers, etc.

A．World population is increasing at a rate of 150 per minute.
B．Lower death rates also contribute to world population growth.
C．The population of Columbia has been doubling every year for 21 years.
D．The United States is usually doubling its population about every 87 years.