Agroup of stars, gas, and dust held together by gravity is a
a.
galaxy
c.
local group
b.
constellation
d.
both a and b

Which is not an example of a  cultural  bond found in a nation-state? a. a holiday traditionb. a common religionc. a favorite placed. a shared history

Find the equation of the line passing through the point (–1, 5) and perpendicular to the line 3x + y = 4.

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks