The World's Water Supply... - 97.2% - thousands of years Ite caps and glaciers – 2.15% - tens of thousands of years Groundwater - .31% - hundreds to thousands of years - .009% - tens of years Atmosphere - .001% - nine days! and - .0001% - two weeks

la respuesta es si te gusta hacer lo que siempre haces cuando nunca ves a alguien en el espejo porque sabes que no siempre están ahí.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.