According to the passage, wireless network has an advantage over the three products mere tioned in_______.

A．It helps people know that ancient trees have no trunk.
B．It provides us new information about the appearance of the earliest forest.
C．It provides evidence for the existence of trees 397 million years ago.
D．It provides evidence for the bloom of trees 397 million years ago.

A．Because they were closely spaced, only 3 to 16 feet apart.
B．Because they were smaller plants and shrubs.
C．Because their branches did not fan out as far as to form a shape like umbrella.
D．Because they had very small leaves like that of fern and dropped easily.