Read the following excerpt from a popular work of fiction. As you read, look for clues that tell you which genre the excerpt falls into. The Tasmanians, in spite of their human likeness, were entirely swept out of existence in a war
of extermination waged by European immigrants in the space of fifty years. Are we such apostles of mercy as to complain if the Martians warred in the same spirit?
The Martians seem to have calculated their descent with amazing subtlety—their mathematical
learning is evidently far in excess of ours—and to have carried out their preparations with a
well-nigh perfect unanimity. Had our instruments permitted it, we might have seen the gathering trouble far back in the nineteenth century. Men like Schiaparelli watched the red planet—it
is odd, by the way, that for countless centuries Mars has been the star of war—but failed to
interpret the fluctuating appearances of the markings they mapped so well. All that time the
Martians must have been getting ready.

What kinds of details help classify this story as science fiction?

plot events occurring far in the future
scientists as main characters
time traveling into the past
an extraterrestrial or alien race​