Understanding that objects exist even when they are not perceived at a given moment is called the concept of 

A small marine amphipod has recently been discovered that carries a bad-tasting organism on its back, which is contrary to its normal behavior. If a fish ingests the pair, it immediately spits them back out. If the amphipod is alone, however, it is readily eaten. There is no apparent benefit or harm in this relationship for the “backpack” organism. This is a case of

An ecosystem includes

Describe the relationship between language and literacy development.

Two-year-olds are not yet able to solve problems.

Fungi cell walls contain this, unlike plant cell walls, which contain cellulose

Which of the following factors can limit the growth of a population?

List three health and nutrition related problems the lower socioeconomic-level child might have when starting school.

Crabs, crayfish, shrimp, and lobsters are all part of this subphylum.

Fishes that include sharks, rays, skates, and chimaeras.