Question

12/23
the horseshoe crab was reclassified more closely with spiders because
it had an exoskeleton
it had a similar circulatory system.
it lived on land
it had poison

Explanation:

To determine why horseshoe crabs were reclassified closer to spiders, we analyze each option:

• "It had an exoskeleton": Many arthropods (like insects, crustaceans) have exoskeletons, so this alone doesn’t justify closer relation to spiders.
• "It had a similar circulatory system": Horseshoe crabs and spiders (both in Chelicerata) share a similar open circulatory system with hemocyanin, which is a key anatomical similarity supporting reclassification.
• "It lived on land": Horseshoe crabs are primarily marine, so this is incorrect.
• "It had poison": Horseshoe crabs don’t have poison, and spiders’ venom is not a defining trait for this reclassification.

The circulatory system similarity is the most relevant anatomical feature for taxonomic reclassification.

Answer:

B. it had a similar circulatory system