Practice question

The right choice is B: Se-Se-Ca-Ca. In PSS-Sec-E-Sensory biology, that matches how the process or concept actually works — the other choices mix up related ideas or use the wrong mechanism. Skip these: A) Se-Pe-St-Ca; C) Pe-Pe-St-St; D) St-St-Ca-Ca. A quick check: if an option needs energy, pumps, or the opposite direction of movement, ask whether that really applies.