In biological terms a cells main purpose is to survive but some important functions of cells are 1. Transports ( of molecules) 2. Chemical Reactions ( I.e Metabolism ) including energy conversion 3. reproduction hope this helps!
The plants give out oxygen so for us humans will live
Option C: elements produce spectra with only few distinct lines.
The spectra are not continuos and are different for every element. This permits to identify elements.
The only one that I can do without google is 47. Sorry that I can't answer the others. The answer to 47 is this: you know that the western side of the hill has the steepest slope because the ovals showing altitude are way closer together. The closer the circles/ovals are, the steeper the slope is.
Sorry if this doesn't help much, but I answered what I could without cheating.
Foxeslair
