The phrase "catch on"(Line 1,Para.3) most probably means ______.

A．People whose house has no space for wireless system.
B．People whose house cannot receive images, sounds or messages.
C．People who have no extra money to afford wireless system.
D．People who prefer to do things in a simpler way.

A．The internal structure shows how ancient trees grew.
B．The CO₂ lever exerts impact on the leaves of ancient tress.
C．Analysis of ancient fossils paint picture of the Earth's earliest trees.
D．The ancient trees have no leaves and few branches.