Answer:
A crime scene investigator wants to use a forensic lamp to look for particles on a carpet at a crime scene. Which technique will she use to find the particle evidence?
infrared technique
Explanation:
infrared technique helps in absorption, emission and reflection which would be used to find the particle evidence
It is definitely not a primary source: this would be a book itself.
Now, is it a tertiary source? I don't think so: the author of the review should have read the book and should only be referring to this book in the review.
I think it's a secondary source.
Explanation: Elephants have been extensively hunted for ivory for more than 300 years, natural selection is often proposed as the underlying mechanism for an increase in the proportion of tuskless or small-tusked elephants in a population.
Chewing a saltine cracker is a physical change