I think the hydra lacks the specialized cells for touch and chemical detection. On the other hand earthworms have touch, light, vibration and chemical receptors along the entire body surface. Both of them are invertebrates (those animals without a backbone), they include insects, worms, jelly fish, spiders among other animals.
Animals that live in estuaries need to adapt to changing salinity levels and the rising and falling of tides. Adaptation is the result of evolution.
<h3>Evolution and adaptation</h3>
The term 'evolution' refers to descendence with modification, which is mainly achieved by natural selection.
Adaptation refers to the process of adjustment that makes organisms in order to fit certain environmental conditions.
Natural selection is the differential survival and reproduction of the organisms better adapted to their environment.
Learn more about adaptation here:
brainly.com/question/1213023
Answer:
primary active transport
Explanation:
primary active transport directly uses a sources of chemical energy ATP to move molecules across a membrane against their gradient
