Read the excerpt from chapter 5 of wheels of change.

by the turn of the century, the bicycle's heyday was over and a new mechanical wonder promised to transport men and women faster and farther than ever before. bicycle manufacturers retooled their factories to build them and bicycle repair shops installed gasoline tanks to service them. the era of the automobile had begun

which aspect of historical context does this excerpt most reflect?

a change in national politics

a change in society and its values

a development in technology

a development in world events

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.