The answer would be the 3rd sentence.
<span>Gideon and Francis took a difficult - but not interesting - science course.</span>
Indoor Plumbing.
Primarily, it has provided a greater level of sanitation in modern life. The use of running water to wash your hands and bathe reduces the likelihood of spreading germs and bacteria. The ability to cleanly remove waste away from heavily populated areas allows for cleaner air, thus, fewer respiratory related illnesses. Ultimately, it has propelled civilizations towards the better quality of life that we enjoy today.
I think he means that humans don’t like being alone. It’s our nature to find someone or have a companion throughout our lives. We instinctfully talk to people to interact or make friends. That’s what I think he means
