Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 24 to 28.

Human beings (24) ______ to protect only the beautiful and non-threatening parts of our environment. We tend to pay more (25) _______ to animals on land than any other large sea animals. Environmentalists have not done much enough to help save the Pacific Ocean sharks (26) _______ population has decreased nearly to the point of extinction. Sharks are among the oldest creatures on Earth, having survived in the seas for more than 350 million years. The fact that they have managed to live in the oceans for so many millions of years is enough proofs of their efficiency and adaptability to change environments. It's time (27) _______ human beings to begin considering the protection of sharks as important part of a program for protection of our natural (28) ________  

Human beings (24) ______ to protect only the beautiful and non-threatening parts of our environment.