Antagonists are substances that bind to receptor sites to block the effects of natural messengers. They do not get transferred into the cell but inhibit the natural communication of the body.
Conclusion: The correct answer is (4) A and C.
A square loop of sides \( a = 1 \, {m} \) is held normally in front of a point charge \( q = 1 \, {C} \). The flux of the electric field through the shaded region is \( \frac{5}{p} \times \frac{1}{\varepsilon_0} \, {Nm}^2/{C} \), where the value of \( p \) is: