What is most closely a central idea of Reagan’s address about the Space Shuttle Challenger?

People brave enough to explore new territory face great risks.

Losing the Challenger was an effect of taking the space program for granted.

An event as tragic as this makes one call into question whether to continue on with these explorations.

The nation cannot let grief hold itself back from carrying on with people’s regular routines.

Which sentence is punctuated correctly?  a.under a microscope; the organisms look a bit like ruffled tennis balls they have armored plates that fit together to make a round shape. b.when the water is disturbed; the organisms respond by glowing this makes swimmers look like floating beams of blue light. c.there is a bay in puerto rico that seems to light up at night; the light comes from tiny organisms in the water. d.the luminescence attracts visitors from around the world people are curious to see; this beautiful otherworldly sight.