[Video] Q23: A student claims that nitrogenous bases pair randomly with one another. which of the following statements in the passage contradicts the student’s claim?

Explanation for Question 23 From the Reading Section on the Official Sat Practice Test 1

Okay. So number 23 actually says it, a student claims that nitrogenous 2 bases pair randomly with one another and we have to prove that they don't. 3 So do basis pair randomly with each other. 4 They do not. Right. So how do we find the evidence for that? 5 So it's not going to be early on in the passage, 6 right? Because we don't even talk about how basis pair until later on in 7 the passage. So I'm going to go ahead and just get rid of a 8 and B and let's look directly at C and D. 9 So either 23 or 27, look at 23, 23 10 says the base are joined together in pairs, a single base from one chain 11 being hydronic, hydrogen bonded to a single base from the other chain. 12 And then 27 says, um, 13 one number of a pair must be period. And the other appear of Medina 14 or to bridge between the two chains. 15 If a pair consists of two periods, for example, we're not the room for 16 it. Well, this right here actually goes against the idea that it's a random 17 pairing. It can't be random because this one is right here, 18 says, if you consisted of two periods, I wouldn't work. 19 So you actually have to have a certain, you have to be a certain 20 type. You have to be a period of pyramiding. This right here then is 21 the answer. It's the one that completely contradicts the idea that could be random 22 because it actually specifies the type that you need. 23 So D is going to be the answer for this.