Ecology and Ecosystems QBA Exam 1 Practice Test 2026 - Free Practice Questions and Study Guide

The intertidal zone blends aquatic and terrestrial challenges, so the best-fit organism is one that can endure being submerged and then exposed to air. A starfish on rocky shores exemplifies this, because many sea stars inhabit this zone and have adaptations to stay moist and respire while out of the water during low tide. Their water vascular system and tube feet let them cling and feed when submerged, while dermal tissues and moist surfaces allow gas exchange during brief exposure to air. In contrast, an estuary is a habitat, not an organism; sharks and anglerfish are adapted to living in water and would not tolerate the dry conditions of the shoreline for significant periods.