Final answer:
Push-ups are the best exercise for improving muscular strength and endurance.
Step-by-step explanation:
The best exercise for improving muscular strength and endurance among the given options is push-ups. Push-ups primarily target the upper body and engage multiple muscle groups including the chest, shoulders, triceps, and core muscles, thereby improving strength and endurance.
Walking and running are great for cardiovascular fitness, but they primarily focus on leg muscles rather than overall muscular strength and endurance.
Bicycling is also a good exercise for cardiovascular fitness and it works the leg muscles, but it doesn't engage as many muscle groups as push-ups do.
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