Proper use of a condom during sexual activity does not guarantee protection against stis.

True
Sometimes the use of condoms can't prevent STIs(sexually transmitted infections) because of the manufacturer fault. STIs that caused by lice is not protected too because the condom doesn't cover hair. Other than that, a condom provides a good physical barrier that prevents diseases that transmitted body liquid. 

If you get a map and put the countries a states all together it forms all one piece you can also tell because of the earth quakes