The pair of characteristics that one must use to classify a fish is the presence of jaw and skeleton type. Agnatha fishes are also called jawless fishes and they lack bony skeletons. Cartilaginous fishes are composed of cartilage skeletons. Bony fishes have bony skeleton structures.
<u>Answer</u>: C) Hydrophobic interior, hydrophilic exterior
<u>Explanation</u>:
- The <em>plasma membrane</em> of the cell defines its boundary and separates its internal components from the external environment.
- The basic components of the plasma membrane include phospholipids, carbohydrates, proteins, and cholesterol.
- The plasma membrane is a phospholipid bilayer, with <em>hydrophobic</em> tails of the phospholipid projecting <em>inwards</em> and the <em>hydrophilic</em> exterior in contact with the external environment.
- <em>Due to this, the plasma membrane has a hydrophobic interior and hydrophilic exterior. </em>
The muscular system allows for movement within the body, for example, during digestion or urination. Smooth muscles in the gastrointestinal or GI tract control digestion. The GI tract stretches from the mouth to the anus. Food moves through the digestive system with a wave-like motion called peristalsis.
