LSAT Reading Comprehension: Science and Law Passages

Question 1

Passage: Scientists have long debated the origins of the Cambrian explosion—the relatively sudden appearance in the fossil record of most major animal phyla approximately 540 million years ago. Traditional explanations pointed to environmental triggers: an increase in atmospheric oxygen, changes in ocean chemistry, or the warming climate following a global glaciation event known as 'Snowball Earth.' More recently, developmental biologists have proposed that the evolution of Hox genes—a family of regulatory genes that control body plan development—may have been the critical internal trigger. These genes, once established, would have enabled rapid evolutionary diversification of body plans without requiring environmental change. Critics of the Hox gene hypothesis argue that it describes a permissive condition rather than a triggering cause: Hox genes made diversification possible but do not explain why it happened when it did. The main point of the passage is:

Accepted Answer

The origin of the Cambrian explosion remains debated, with both environmental and genetic explanations proposed.

Answer

The passage presents both environmental and genetic explanations and notes that the Hox gene hypothesis faces criticism, conveying ongoing debate without endorsing a conclusion.

Question 2

Passage (continued from above): The critics' objection to the Hox gene hypothesis is best characterized as:

Accepted Answer

A conceptual distinction between enabling conditions and active causes.

Answer

The critics argue that Hox genes describe a 'permissive condition'—they made diversification possible—but don't explain the timing, distinguishing enabling from triggering causes.

Question 3

Passage: The doctrine of promissory estoppel developed in common law as an equitable remedy to prevent unjust enrichment in cases where a party made a clear and definite promise that the promisee reasonably relied upon to their detriment, even absent formal consideration. The Restatement (Second) of Contracts codified this doctrine, requiring: (1) a promise that the promisor should reasonably expect to induce action or forbearance; (2) that did in fact induce such action or forbearance; and (3) that injustice can be avoided only by enforcement of the promise. Courts have applied promissory estoppel with varying degrees of liberality. Some jurisdictions require a high threshold of detrimental reliance, demanding that the promisee's reliance be objectively reasonable and the detriment substantial. Others have broadened the doctrine to encompass situations where the reliance is relatively minor if the promise was sufficiently clear. According to the passage, promissory estoppel developed primarily to address:

Accepted Answer

Situations of unjust enrichment resulting from reliance on promises made without formal consideration.

Answer

The passage explicitly states promissory estoppel developed 'to prevent unjust enrichment in cases where a party made a clear and definite promise that the promisee reasonably relied upon to their detriment, even absent formal consideration.'

Question 4

Passage (continued from above): Which of the following best describes the jurisdictional variation described in the passage?

Accepted Answer

Some courts apply a strict threshold for reliance while others extend the doctrine to cases of minor reliance on clear promises.

Answer

The passage states some jurisdictions 'require a high threshold of detrimental reliance' while others 'broadened the doctrine to encompass situations where the reliance is relatively minor if the promise was sufficiently clear.'

Question 5

Passage: The theory of plate tectonics, now the foundational framework of modern geology, was initially met with ridicule when Alfred Wegener proposed continental drift in 1912. Wegener's hypothesis that the continents had once formed a single landmass—Pangaea—and had since drifted apart was based on the geometric fit of continental coastlines, similar fossil assemblages on separated continents, and matching geological formations across ocean basins. However, Wegener could not explain the mechanism by which continents moved, and the geological establishment rejected his ideas for decades. The discovery of seafloor spreading in the 1960s, which revealed that new oceanic crust is continuously created at mid-ocean ridges and destroyed at subduction zones, provided the missing mechanism. The integration of seafloor spreading with continental drift formed the comprehensive theory of plate tectonics. The passage suggests that Wegener's theory was rejected primarily because:

Accepted Answer

He could not account for the force or mechanism that moved continents.

Answer

The passage explicitly states Wegener 'could not explain the mechanism by which continents moved, and the geological establishment rejected his ideas for decades.'

LSAT - Law School Admission Test Practice Test

LSAT - Law School Admission Test Practice Test

LSAT Reading Comprehension: Science and Law Passages