Which of the following animals is not an arthropod？ A: house lizard B: ladybug C: crab D: centipede

Millipedes (马陆/千足虫) belong to the arthropod subphylum ( ) A: Hexapoda. B: Crustacea. C: Trilobitomorpha. D: Chilopoda. E: Myriapoda.

The inner layer of the exoskeleton (外骨骼) of an arthropod is called the ________. It contains chitin (几丁质), and its outer region is hardened. The outermost layer of the exoskeleton is waxy and impermeable to water. A: epicuticle (上表皮) B: procuticle (原表皮) C: hypodermis (真皮) D: basement membrane (基膜)