The elements listed in the choices are radioactive materials. These materials are very unstable because of the high neutron-to-proton ratio in the nucleus. Because of this, they spontaneously undergo nuclear reactions by giving off sub-particles in order to lower the ratio. They emit radiation in the form of alpha, beta or gamma.
Half-life is the length of time it needs to completely react half of the original amount. For example, it would take Bismuth 60.5 seconds to use up half of its amount. Therefore, the lower the half-life the faster the reaction is and the lesser the residual amount will be. With that being said, the answer would be Bismuth because it only takes seconds.
Lines of latitude and longitude help you find a certain location on a map
Answer: Chicxulub, Mexico.
Explanation:
The Chicxulub crater is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named.
The Earth rumbles and a hiss of steam issues from the top of Mt Ruapehu. Are these two events related? Is the earthquake caused by the volcano? Or is the steam caused by the earthquake?
Tectonic plates
When Alfred Wegener first proposed the idea of continental drift (the precursor idea to plate tectonic theory), it didn’t quite explain the full story. While he correctly showed that Africa and South America fitted together, his model wasn’t able to explain the violent forces that occur around the Earth’scrust.
