Answer:
Models are used to simulate reality and make predictions. The major limitation of models is that they are 'idealizations' or 'simplification' of reality and thus cannot possibly replace reality. A number of assumptions are made during modeling and this causes differences between model and reality.
 
        
             
        
        
        
1. No
2. The amount of mass
3. Gravity
4. Yes because the paper most likely flew away and the crumble paper most likely hit the floor
        
             
        
        
        
Answer:
Polymerase chain reaction machine
Primers
Petri dishes
Test tubes
Pipettes
DNA Polymerase
Free nucleotides
The organism to be identified
Explanation:
To identify the genetic makeup of an unknown organism, the nucleotide sequences fond in the Deoxyribonucleotide (DNA) of a known organism is matched to the DNA of some known organisms. If there is a certain degree of sameness in most of the matched parts, then the unknown organism can be said to be related to the known organism. This is a comparative study. 
To carry out this identification, items used include; primers, the PCR machine, test tubes, DNA polymerase, free nucleotides, etc.