What is the main idea of the passage? A. If we did not have the International Space Station, medical
advances would cease.
a
B. Insuring that we have healthy astronauts provided the reasons for
building the International Space Station.
C. The International Space Station helps scientists understand how
gravity causes aging.
CD. The International Space Station provides a place where research
can be conducted that helps us understand human health.

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.