適用 and 適応: Applying a rule and adapting to an environment
Compare applying a rule to shops or a discount under a stated condition with adapting to a new life or dry conditions. Distinguish a standard and its target from a target and its environment.
Applying a standard to a target
適用 means application or applicability. 「来月から新しい規則が全店舗に適用される。」 says a new rule applies to all shops starting next month. The rule is the standard and the shops are its targets.
「学生証を見せれば、この割引が適用されます。」 makes the discount conditional on showing a student ID. Removing that condition would broaden the stated scope.
Adapting to an environment
適応 means adaptation or adjustment. 「新しい生活に適応するまで少し時間がかかった。」 says it took a while to adjust to a new life. The new life is the setting to which the person adapts.
「この植物は乾燥した環境によく適応している。」 says a plant is well adapted to dry conditions. This example shows that 適応 is not limited to people.
Identify the direction of the relation
In the shop example, 適用 concerns a rule being applied to the shops. The plant’s 適応 concerns a target fitting its environment. The standard, target, and environment have different roles.
The distinction is not objects versus people. Application timing and the student-ID condition limit the stated scope, while adaptation concerns the new life or dry environment. These sentences do not supply discount calculations or cultivation methods.
How does 適用 of a rule to shops differ from a plant’s 適応 to dry conditions?
Show the answer and why
適用 concerns applying a standard to its targets, while 適応 concerns a target adapting to its environment. Identify the rule-to-shop relation separately from the plant-to-environment relation.