This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to work out chest muscles without weights
Perform basic pushups.
There are many variations of pushups that can help you build your chest muscles, but for beginners, there's nothing wrong with basic, ordinary pushups. That said, when starting push ups, avoid lowering your chest too close to the ground.

OPT:
[+] Lowering yourself too close to the floor can tear tissues in the shoulder. Gradually work your way to lowering yourself slightly closer to the floor over time.
[+] Keep your chest up and keep your back engaged and your elbows bent at a right angle. When you're ready to begin moving your chest towards the mat, hang on to an ordinary weight bar or a weighted resistance band to complete chest presses.
[+] Lie on your back with your feet firmly on the floor. Extend one arm straight above your head with a small round tip.
[+] However, with a few repetitions you should manage to perfect your pushups before you switch to heavier, more demanding lifts. As with any physical activity, though, pushups should be performed with the intention of building up your whole upper body.
The answer is:
Lowering yourself too close to the floor can tear tissues in the shoulder. Gradually work your way to lowering yourself slightly closer to the floor over time.