PLZ HELP ME

Chelsea is researching an organism. Her organism has jointed limbs and an exoskeleton. It also obtains air through air tubes. Chelsea’s organism is classified as a/an —
OPTIONS: amphibian
echinoderm
mollusk
arthropod

Arthropod.

Explanation:

Arthropods have an exoskeleton & jointed limbs.  Insects and some other land arthropods breathe through a system of tiny body tubes called tracheae. Some examples of arthropods are a spider or a scorpion.

many phylogenetic trees have a single lineage at the base representing a common ancestor. a lineage that evolved early from the root and remains unbranched is called basal taxon. when two lineages stem from the same branch point, they are called sister taxa.

can i get the brainliest pls

explanation:

if someone had the list of traits you provided