Analogy type questions:
$(1)$ Coconut milk : Zeatin : : $ABA$ : ...............
$(2)$ Phenolic acid : Seed dormancy : : Cold treatment : ...............

(A) $(1)$ Stress. $ABA$ (Abscisic acid) is known as a stress hormone because it increases the tolerance of plants to various kinds of stresses.
$(2)$ Vernalization. Cold treatment is a method used to induce flowering in plants,a process known as vernalization.