Problem description:

As the title!

Analysis:

A grass with strong vitality can continue to develop into a new grass as long as there is a little part left that can absorb nutrients. Therefore, when weeding, it is necessary to uproot the roots that absorb nutrients and water and cut off the back road of grass. But even if it is uprooted, new grass will grow in the field without grass roots, because the grass seeds are too small. If you touch them gently, many grass seeds will fall into the soil.