If you are talking about frequency in terms of waves, it is in seconds^-1
This is because the modern lifestyle we're living and people are living in the US is very taxing and can cause people to feel extremely bad about themselves for prolonged periods of time. Furthermore, it's also possible people/doctors are misdiagnosing depression and saying someone is depressed when he or she actually isn't.
Answer:
I think C. Petri dishes
Explanation:
"The most common growth media nutrient broths (liquid nutrient medium) or LB medium (Lysogeny Broth) are liquid. These are often mixed with agar and poured into Petri dishes to solidify. These agar plates provide a solid medium on which microbes may be cultured."-https://courses.lumenlearning.com/boundless-microbiology/chapter/culturing-bacteria/
I hope this helps!
