The principal greenhouse gases in our present atmosphere are ...

[asan beg]

The principal greenhouse gases in our present atmosphere are
 
  A) hydrogen and helium.
  B) hydrogen sulfide and carbon disulfide.
  C) water vapor and carbon dioxide.
  D) methane and ammonia.
  E) sulfuric acid vapor and carbon dioxide.

Question 2

What is a CCD, and how does it work? Why is it replacing film?
 
  What will be an ideal response?

[Jody Vaughn]

Answer to Question 1

C

Answer to Question 2

A charge coupled device consists of a grid of thousands of light-sensitive pixels that build up a digital image that can be stored on computer as light strikes it. It is digital, so it can be placed directly on magnetic tape or disks, or sent over a computer network. CCDs are also much more sensitive to fainter objects than are the fastest photo films.

[asan beg]

Thanks for the timely response, appreciate it

[pangili4]

Excellent