Which is the most reliable source for a presentation about the history of washington, dc’s smithsonian museums?

Can anyone plz with this question i accidentally posted on physics it's 99 points plus this 5 ponts and will mark as brainliest link :

What is the main problem with the following critique? “you put some thought into it, but you obviously do not care much about the topic you are presenting.” a. it is not ethical. b. it is not constructive c. it is not specific. d. it is not behavior focused.

Walking is not the most exciting form of exercise a person can take on for fitness. yet it is low impact and requires no fancy equipment. that makes walking a simple activity for those new to exercise. walking is less likely than other exercises to cause injury to leg tendons and muscles. all it requires is a good pair of sneakers-no cables, stylish outfits, or weights required. of course, a person could increase the benefit of a workout by adding weights or speed walking. identify the main idea of this paragraph. walking is a difficult and safe exercise for beginners. walking is an easy and safe exercise for beginners. walking is a boring and dangerous form of exercise. walking is an exciting and very effective form of exercise.