Yes, nosebleeds do tend to occur more often during pregnancy. Pregnancy can cause the blood vessels in your nose to expand, and your increased blood supply puts more pressure on those delicate vessels, causing them to rupture more easily. Although it's unpleasant and inconvenient, an occasional minor nosebleed is generally harmless.
The higher the energy of the gamma rays, the thicker the shielding made from the same shielding material is required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL).
This is a daft question. Our eyes can detect visible radiation, our skin can detect infra-red, our skin can also react to ultra-violet radiation by tanning, and producing skin cancers. Our brains can react directly to the impact of gamma rays ( as seen by astronauts ) and some microwaves will cause us to heat up internally.