There are many reasons, they can be grouped into 3 categories - Professial letters (reference letters, resignation letters) - Personal (Diaries, love letters) - Journals (Diaries, logs)
Regardless of the type of writing, they are all used to express ideas and thoughts that can branch over the areas of personal reflection, technical feedback, and serious matters.
The main idea in the paragraph is that women played a bigger role in prehistoric progress than is commonly thought.
Two details supporting this claim are statues and cave paintings from prehistoric times, which represent scenes from the life of the people who created them. This art has apparently been studied by experts and seems to provide evidence of women's various pioneering roles.
Women are likely to have invented pottery, baskets and gardening because they had to watch over young children and therefore were staying near the living spaces instead of going out hunting, for example. This means that they had more time to spend experimenting with tools and techniques. What's more, because they were not hunting, women were expected to help men bring food to the community by growing crops, which is why it is thought they invented gardening.