Answer:
The sound intensity of train is 1000 times greater than that of the library.
Explanation:
We have expression for sound intensity level,

A train whistle has a sound intensity level of 70 dB
We have

A library has a sound intensity level of about 40 dB
We also have

Dividing both equations

The sound intensity of train is 1000 times greater than that of the library.
False, we lack cell walls whereas they have cell walls.
Explanation:
everything can be found in the picture
Simply be used as a reference point <span>to describe its position. a fact forming the basis of an evaluation or assessment; criterion. They had few cultural </span>reference points<span> in common.</span>