Question

arthropods are characterized by
molting and only two germ layers.
an endoskeleton and protostome development.
protostome development and jointed appendages.
segmentation and deuterostome development.

Explanation:

• Arthropods are protostomes (during embryonic development, the blastopore forms the mouth first).
• They have jointed appendages which are a key characteristic.
• Arthropods have three germ layers (ectoderm, mesoderm, endoderm), so the option with two germ layers is wrong.
• They have an exoskeleton, not an endoskeleton.
• They are protostomes, not deuterostomes (in deuterostomes, the blastopore forms the anus first).

Answer:

protostome development and jointed appendages.