2: answer structure (this is how i would structure my answer, but you can change it if you like to!)
In my opinion, walking your dog for 20 minutes a day reduces the risk of heart disease is the best example for proving that owning pets is a part of a healthy lifestyle. Evidence to show this is, your heart is a vital part of your respiratory system and needs oxygen to pump around the body. A good health needs fresh and clear oxygen of course, so outside in the fresh air is the best for your health. Further to this is, heart disease does happen by physical inactivity, which is caused by lack of movement and stretching in the body. So being outside to walk your dog is a great way of being protected from this heart disease. if a human is outdoors for 20 minutes a day, they will also get fresh oxygen in their body which at the same time makes someone feel fresh and also healthy, by the heart having good and enough fresh oxygen to pump through the bloodstream.
Also, owning a dog is a big part of your responsibility, which proves my point of the privilege of being outside for 20 minutes a day. Even if an individual ever doesn’t want to be outside, they most likely have to, since they need to take the responsibility to walk their dog. This gives them a healthy lifestyle of walking for 20 minutes, which will also reduce chance of obesity, arthritis and laziness when they get used to this routine.
Therefore, answer 2 has the most important claim to a healthy lifestyle.
Hope this helps!!