Option 1 -> Nature is eternal and not mortal, and the passage uses nature as examples to teach lessons, not as something we possess.
Option 2 -> Animals are mentioned separately in the passage and the context refers to something humans possess ("this" frame).
Option 3 -> Land is neither perishable nor mortal in the way described, and doesn't fit the context of the sentence.
Option 4 -> The phrase "perishable and mortal frame" refers to our physical body that will eventually die, and the passage questions its purpose if not used to serve others.
Hence, Option 4: Human body -> "Mortal frame" is a literary/poetic expression for the human physical body that is subject to death. The passage emphasizes that this temporary body should be used selflessly for others' benefit, just as nature's elements serve humanity despite enduring hardships -> correct