HanesMen's Cotton, Moisture-Wicking Crew Tee Undershirts, Multi-Packs Available

Is it considered an undershirt or a regular shirt ?

What's in a cotton tee to have a prop65 warning? >"this product contains chemicals known to the state of california to cause cancer and birth defects"

Will these shrink?

How long is the tee . Will the tee show under a polo?