Latent Impressions and DNA

Topic #1

You have studied some difficult surfaces for obtaining latent fingerprints in past units. What type of surface may be difficult to obtain touch DNA from? How would the environment affect this fragile evidence? 90-100 words. 

Topic #2

Describe how you would collect a fingerprint from a weapon that could possibly have touch DNA on it as well. How would you collect the possible DNA? Which would you collect first? 90-100 words.