Final answer:
The subsistence method using simple tools, no irrigation, and no fertilization to grow crops is referred to as gathering and hunting, which relies on natural resources and is one of the oldest human subsistence strategies.
Step-by-step explanation:
The type of subsistence method that involves using simple tools, no irrigation, and no fertilization to grow crops is known as gathering and hunting. This subsistence strategy is one of the most ancient ways humans obtained food, relying on the collection of wild plants and hunting wild animals. It does not involve the modern agricultural techniques of planting crops in large, controlled plots with the aid of irrigation and fertilizers. Instead, it depends on the natural abundance of resources available in the environment.
Gathering and hunting were the primary means of survival for human groups up until about 10,000 years ago and are characterized by high mobility and egalitarian social structures. Though it is far less common today, some groups continue to practice this lifestyle, which requires extensive knowledge of the local flora and fauna. As a subsistence strategy, gathering and hunting focus on the direct use of environmental materials to meet the needs of the community.