Which role do ultrafine particles play in dirty air?

They contribute to less than 13,000 premature deaths a year.
They can worsen symptoms for people with breathing difficulties.
They are easily removed from the air when people see them floating.
They are constantly filtered by the nose, which prevents lung absorption.

They can worsen symptoms for people with breathing difficulties.

Explanation:

The other person is correct, I don't know what else to say because I don't want to feel like I'm copying them but I just wanted to confirm that their answer is in fact correct. :)

Explanation:

1. dermis

2. chemical

3. urine

4. viruses

5. antibodies

a researcher conducts an experiment on the secretion of a particular hormone in mice. scientists inject mice with a substance that stimulates the production of the hormone. the scientists then test the levels of hormones produced by the mice. the tool used to measure the hormones consistently detects the levels at 10 points lower than the actual hormone levels in the mice. this tool makes measurements, but the measurements aren't .

explanation:

no u