[Video] Q22: The authors use the word “backbone” in lines 3 and 39 to indicate that

Explanation for Question 22 From the Reading Section on the Official Sat Practice Test 1

Okay. So number 22 says the authors use the word backbone in lines three 2 and 39 to indicate what? So we have to go just actually just go 3 back to, um, 4 lines 3 39, look at how I'm using the word backbone there, 5 and then kind of predict the answer based on what we see. 6 Um, let's see. So three, 7 the molecule of a very long chain, 8 the backbone of which consists of a regular alternation of sugar and phosphate groups. 9 Okay. So the molecules a very long string, the backbone of which consists of 10 a regular alternation of certain prosecutors. So the backbone is the thing that's repeating 11 between sugar and phosphate, 12 sugar and phosphate, sugar and phosphate. So the backbone is like the base of 13 it. It's the thing that's repeating. Um, 14 and then what was the other line? 39. Let's see. 15 Okay. The phosphate sugar back, 16 one of our model is completely irregular, but NEC went to the pairs that 17 basis confined to the structure. 18 Okay. Again, they're specifically referring to the backbone as the thing that's alternating between 19 phosphate and sugar, phosphate, sugar, phosphate, sugar, it's like a pattern. 20 Um, so what is, is it a only, very long because the DNA can 21 be taken from an organism in the spinal column? No. 22 Does it indicate that be the main structure of a chain? And do you 23 know how he was confused is composed of repeating units? 24 Yes. The answer to be B, because we're talking about how you alternate between 25 phosphate and sugar, AKA ...