A(n) is any substance that the white blood cells recognize as foreign.

Answer : Antigen

Antigens are any substances that the immune system can recognize.

Hope this helps. - M

Hello! i believe that it is okay, but you should limit on how much you go in a jacuzzi, hot tub, sauna etc. the rise in temperature may effect the development of you unborn baby and could cause some birth defects most likely in the first 3 months or 12 weeks of pregnancy. the recommended amount of time to be in a jacuzzi while pregnant would be 10  minutes or less.i hope this !

Answera tightly sealed house with an unvented water heater;