Question

linus pauling (1901 - 1994) was an american scientist. he studied dna, the material that carries a living organism’s genetic information.
from the shape of dna
1
like most other scientists, pauling was not interested in dna until 1952, even though swiss biologist friedrich miescher had discovered dna in 1869. but what was dna? scientists knew only a little. it came in long strands, and each strand had a phosphorus - sugar backbone. there were also nucleic bases, which stuck out from the backbone like knobs on a spine. but the shape of the strands and how they linked up were mysteries—important mysteries. as pauling showed with hemoglobin, shape can affect how molecules work. soon the shape of dna became the most important question in biology.
2
and pauling, like many others, assumed he was the only one smart enough to answer this question. this wasn’t, or at least wasn’t only, arrogance: pauling had simply never been beaten before. so in 1952, pauling sat down at his desk in california to crack dna. he decided, incorrectly, that the bulky nucleic bases sat on the outside of each strand with the phosphorus - sugar backbone toward the molecule’s core. pauling also reasoned that dna was a triple helix, with three ribbons of the phosphorus - sugar backbones forming a spiral. unfortunately for pauling, his data came from a dried - out dna sample, which made the molecule seem more complicated. but on paper, all this seemed possible.
3
everything was humming along nicely until pauling asked a graduate student to check his calculations. the student did and was soon tying himself
this question has two parts. answer part a, and then answer part b.
part a
which claim does the author develop throughout the passage regarding linus pauling?

1. pauling lost the race to discover the shape of dna in part because he was overly confident.
2. pauling has been unjustly excluded from the praise given to scientists who researched dna.
3. pauling sometimes cheated in order to prevent other scientists from solving dna before he did.
4. pauling should have gotten credit for determining that dna strands were in the shape of a helix.

part b
which sentence from the passage best helps develop

Explanation:

For Part A: The passage states Pauling assumed he was the only one smart enough to solve DNA's shape, made incorrect structural assumptions, and used flawed data from a dried sample, which led to his incorrect model, indicating his overconfidence contributed to losing the race to discover DNA's correct shape. The other options are unsupported: there is no mention of unjust exclusion, cheating, or uncredited helix work.
For Part B (note: the full passage is cut off, but based on Part A's correct claim, the sentence that best supports it is "And Pauling, like many others, assumed he was the only one smart enough to answer this question. This wasn't, or at least wasn't only, arrogance: Pauling had simply never been beaten before." as it establishes his overconfidence that led to his incorrect work.)

Answer:

Part A: 1. Pauling lost the race to discover the shape of DNA in part because he was overly confident.
Part B: And Pauling, like many others, assumed he was the only one smart enough to answer this question. This wasn't, or at least wasn't only, arrogance: Pauling had simply never been beaten before.