Please answer fast

1. Complete the following sentences using words from the lesson.

a. ___________________ are steep-sided volcanoes that erupt a variety of lavas that are stiff or pasty and do not flow easily.

b. There are four major groups of lava rocks: ___________________, ________________________, _____________________, ____________________.

c. Volcanoes have a ___________________ at the summit formed around a vent through which lava steam, ashes, etc. are expelled.