GEOLOGY

Detailed explanation-1: -There are two small phyla with species that exist today that are very closely related to arthropods by molecular analysis. These are the Onychophora and the Tardigrada.

Detailed explanation-2: -What two major habitats of Earth were arthropods the first animals to explore? Devonian period-tiny lichens and lush plants provided a new frontier for life; Plant life growing densely provided micro environments.

Detailed explanation-3: -Arachnids have a fused head and thorax and have four pairs of legs. The largest group of arthropods is the insects, including grasshoppers, butterflies, beetles, and cockroaches.

Detailed explanation-4: -insects; myriapods (including centipedes and millipedes); arachnids (including spiders, mites and scorpions); crustaceans (including slaters, prawn and crabs).