As­tronomers found stars careening around these centers, zooming at previously unheard-of speeds in their orbits. The motion was like an accelerating ice skater pulled around her partner in a tight twirl – or like a fish caught in a superstrong whirlpool. Something ex­treme had to be in the middle of each of those galaxies. You might be able to guess what this was, but for scientists, the best answer came as a shock. In 1994 telescopic evidence confirmed the amazing cause: a supermassive black hole, with the mass not of one imploded star, not of two, but of millions – maybe even billions.

—A Black Hole Is NOT a Hole,
Carolyn Cinami DeCristofano

Which connection helps the reader understand how supermassive black holes were found?

careening stars and orbits
astronomers and telescopic evidence
fish and whirlpools

Read the rough draft of a student's conclusion to anargumentative editorial.(1) year-round schooling would student achievement.(2) not so much information would have to be crammed intonine months. (3) furthermore, the elimination of long breaks,particularly summer break, would significantly reduce"learning loss" and the additional time wasted at thebeginning of each academic year to reteach previouslylearned material. (4) it is clear that year-round schooling students learn and retain more. (5) the united staleis not the only country to experiment with a year-roundschool schedule. (6) although many still claim that evidenceabout year-round school and its link to higher achievement isinconclusive, these people need to open their eyes and seethat students in these schools consistently score higher oncertain assessments than students who attend schools withtraditional nine-month calendars. (7) it is about time that wereplaced our outdated and inefficient school calendars.which best revises sentence 6 to create a more appropriate and respectful tone