Answer:
the presence in or introduction into the environment of a substance which has harmful or poisonous effects.
Because they are on a surface,
Answer:
A sound wave with 15,000 Hz
Explanation:
Humans can averagely hear up too 20,000 Hz. So around 15,000 would make most sense.
Answer:
The additional exposure of soil layers.
Explanation:
Antibiotics are administered by humans, so less contact with humans won't cause an increased use of antibiotics. The prevention of invasive plant species is not a problem, nor would it be caused by improper management of free range animals. Mental Illness in animals is usually caused by being put in small enclosure or living in poor conditions, not by being allowed free range. Therefore, the answer is the additional exposure of soil layers, since excessive grazing can decimate plant and soil layers.
I hope that helped!
