Q: 77 (SSC/NA)
question_subject:
Science
question_exam:
SSC
stats:
0,6,7,5,1,1,6
keywords:
{'vertebrates': [1, 0, 0, 0], 'exoskeleton': [1, 0, 0, 0], 'chondrichthyes': [1, 0, 0, 0], 'amphibia': [0, 0, 0, 1], 'mammalia': [1, 0, 0, 2]}
Option 1: Amphibia - Amphibians, like frogs and salamanders, do not have an exoskeleton. Instead, they have a soft and moist skin.
Option 2: Mammalia - Mammals, including humans, do not have an exoskeleton. They have an internal skeleton made of bones.
Option 3: Aves - Birds also do not have an exoskeleton. They have a lightweight skeleton made of bones.
Option 4: Chondrichthyes - This is the correct option. Chondrichthyes, which includes sharks and rays, do not have an exoskeleton. They have a cartilaginous skeleton, which is made of cartilage rather than bone.
In conclusion, the correct option is option 4, Chondrichthyes, as they are vertebrates that lack an exoskeleton.