Science Facts and General Knowledge Quiz

The lungs never completely empty. Even after maximum exhalation, about 1 liter of residual air remains (residual volume). Each breath only exchanges a portion of the lung's air capacity, which is why we need multiple breaths to affect air quality changes. The answer is correctly False.

Extra ribs (cervical ribs) are rare, occurring in about 1 in 200-500 people (0.2-0.5%), not 5% (1 in 20). Most people have the standard 12 pairs of ribs. The claimed answer (B - False) is correct.

While nitrous oxide (laughing gas) was used in dentistry by Horace Wells in 1844, it wasn't reliably effective. Crawford Long used ether for surgery in 1842 (though unpublished), and William Morton's successful 1846 public demonstration of ether is considered the milestone. Medical historians consider ether the first effective surgical anesthetic, not laughing gas. The answer is correctly False.

Giraffes have equal-length legs on all four limbs. What may create an illusion is the slope of their back and the positioning of their neck, but anatomically their front and back legs are similar in length. The answer is correctly False.

The pupil appears black because it's an opening that allows light to enter the eye - we're essentially looking into the dark interior of the eye. It doesn't have pigment; it's a hole/aperture. The answer is correctly False - it's not actually colored black, it just appears that way.

This is tricky - the cornea IS the most successfully transplanted organ and has the lowest rejection rate because it's avascular (no blood vessels), meaning immune cells don't easily reach it. However, saying 'only organ' and 'without ANY risk' is incorrect because corneal transplants CAN still be rejected, though it's rare. The claimed answer (B - False) is correct because the statement makes overly absolute claims.

Ears perform multiple critical functions beyond hearing. The inner ear contains the vestibular system which is essential for balance, spatial orientation, and coordinating movement. People with inner ear damage experience severe balance and dizziness issues. The answer is correctly False.

Laughing gas (nitrous oxide) was discovered in 1772 and used for recreational purposes and dental procedures in the early 1800s, but the first successful public demonstration of surgical anesthesia was ether in 1846 by William T.G. Morton. Laughing gas was not the first anesthetic used for surgery.

Approximately 1 in 200 to 1 in 500 people are born with an extra rib (cervical rib), not 1 in 20. This is much rarer than the statement suggests.

The cornea is avascular (has no blood vessels), which means it lacks the immune cells that typically cause transplant rejection. This makes it unique among transplantable organs - it can be transplanted without the risk of rejection that other organs face.

Despite their sloping back, a giraffe's front legs and back legs are actually approximately the same length. The illusion that front legs are longer comes from their body shape and the way they stand, but anatomically all four legs are similar in length.

The pupil is an opening that appears black because light entering it is absorbed by tissues inside the eye and doesn't reflect back. It's like a room with open windows viewed from outside - dark because light goes in but doesn't come back out. The statement claims the pupil IS black, which is misleading.