Describe a way that people might be able to solve each envioronmental problem listed below. coal mining can harm habitats and cause pollution.

The answer for #3 is c but i don't know why

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?

Which statement best describes the liquid state of matter? a. it has definite shape but indefinite volume. b. it has definite shape and definite volume. c. it has indefinite shape and indefinite volume. d. it has indefinite shape but definite volume.