The concept of 'biological immortality' has long fascinated scientists, yet its practical implications remain poorly understood. Recent research on the hydra, a freshwater invertebrate, suggests that its stem cells possess an extraordinary capacity for continuous self-renewal, effectively bypassing senescence. However, this does not imply invulnerability; hydras still succumb to predation, disease, or environmental stress. In contrast, some species of jellyfish, such as Turritopsis dohrnii, can revert to an earlier developmental stage after reaching maturity, a process akin to cellular reprogramming. While these discoveries hint at mechanisms that could inform human aging research, experts caution that translating such regenerative abilities to complex organisms like mammals is fraught with obstacles, including the risk of uncontrolled cell growth, which could lead to cancer. Thus, while biological immortality offers a compelling model for studying longevity, its direct application to human medicine remains speculative at best.
❓ According to the passage, what is a major challenge in applying the regenerative mechanisms of organisms like hydras and jellyfish to human medicine?
A. A. These organisms are too evolutionarily distant from humans for any comparison.
B. B. The regeneration process may trigger harmful cell proliferation, such as cancer.
C. C. Human stem cells cannot be reprogrammed under any circumstances.
D. D. The lifespan of hydras and jellyfish is too short for meaningful study.
✅ 正确答案
B. The regeneration process may trigger harmful cell proliferation, such as cancer.
IELTS Reading Tips
Skim the questions first, underline keywords, then locate in the passage
Watch for paraphrasing; correct answers are often reworded
Be wary of absolute statements (all, always, never) — usually wrong
Pay attention to content after transition words (however, but, yet)
Manage time: about 20 minutes per passage; skip difficult questions first