Which claim is the narrowest and most focused? a. hydraulic fracturing is not as dangerous as people think, and natural gas is an important byproduct. b. zoos do not provide adequate habitats for elephants, nor do orangutans thrive in captivity. c. the government should cut welfare programs; homelessness among veterans is a major problem. d. schools should move away from standardized testing because tests often do more harm than good.

D.Schools should move away from standardized testing because tests often do more harm than good.

Explanation:

Claim D is focused on testing in schools and is, therefore, the narrowest of all.

Claim A seems to be focused on hydraulic fracturing and how harmless it is, yet it also mentions natural gas as an important byproduct.

Claim B is about inadequate zoo habitats for two different species of animals, so it cannot be considered the narrowest and most focused claim.

Claim C seems to be focused on cutting welfare programs, yet it also mentions the problem of homelessness among veterans. Not the narrowest claim either.  

the effect is, the moon appears to change shape overtime

explanation: