Materiales que no dejan pasar la luz atravezde ellos

your answer is "the 1950's"

you need more balloons

yes

no

blue is scattered more than other colors because it travels as shorter, smaller waves. this is why we see a blue sky most of the time.

the wetland preservation movement began in the u.s. in earnest with the clean water act (cwa) of 1972. although not specifically written to protect wetlands, the cwa is comprised of a series of regulations designed to prevent pollutants from contaminating u.s. waters.