Hello there!
Your answer would be "They build Dams"
The reason why "They build dams" would be the correct answer is because humans building dams has nothing to do with the environment shaping the human life. When you think about it, dams wouldn't have change the way humans act, since dams are something that doesn't have to do with the human life, or would not be the study of Anthropology. Anthropology is the study of human life, therefore building a dam has nothing to do with the human life. If an Anthropologist were to learn more about the human life and how the environment changed it, a dam wouldn't have changed the life of a human because a dam was artificially made, a dam didn't come naturally in this earth. This is the reason why this answer choice would be correct.
Lets dive in to why the other answer choice are incorrect:
Answer choice "they wear heavy clothing in the winter" is incorrect because:
This shows that when the environment is too cold, humans would have to wear heavy clothing in order to survive, this changed the human life because the humans needed to do something to stay warm, and that was by making heavy clothing. Let's bring back Anthropology. If an Anthropologist was to look at how the environment changed the human life, they would notice that the environment being too cold changed the human life, due to the fact that the cold changes the body temperature, which affects the human body if it's not kept warm. This is the reason why this answer choice would be incorrect.
Answer choice "They wear light clothing in the summer" is incorrect because:
This shows when the environment gets too hot, humans wouldn't need to wear heavy clothing, they would need to only wear light clothing so they won't overheat. If an Anthropologist was to look at how the environment changed the human life, they would notice that the environment being too hot changed the human life, since the hot environment causes the human body to get hotter, which is bad because the human body would just overheat, and probably pass out. The human life are changed by the hot environment because humans needed to figure out what to do to keep their body cooler, while still having clothes on. This is the reason why this answer choice would be incorrect.
Answer choice "they install weatherproof windows" is incorrect because:
This answer choice would be IRRELEVANT to what the question is asking. A human installing weatherproof windows is actually cutting out the environment since the windows would block the nature of the weather in the environment. An Anthropologist can't study how the human life changed because of the environment if a window is blocking the environment from the human. This is the reason why this answer choice would be incorrect.