There are two types of primroses in the Xishuangbanna Botanical Garden, one is self-pollination, and the other is non-self-pollination, which depends on insect pollination. In recent years, the number of pollinating insects has decreased significantly. In addition, a non-self-pollinating cherry tree Grass produces fewer seeds than self-pollination. Obviously, non-self-pollinated primroses have worse propagation conditions than self-pollinated ones. However, non-self-pollinated primroses are more common in botanical gardens than self-pollinated ones. Primrose. Which of the following judgments is the least helpful in explaining the above phenomenon? ['Non-self-pollinating primroses are native plants, while self-pollinating primroses were introduced from abroad a few years ago.', 'In previous years, the ratio of non-self-pollinated primrose and self-pollinated primrose in the above-mentioned botanical garden was about 5: 1.', 'When the two types of primroses are mixed, the nutrients in the soil are more easily absorbed by non-self-pollinated primroses, which often leads to the withering of self-pollinated primroses.', 'In the above botanical gardens, in order to protect pollinating insects from tourists, non-self-pollinated primroses are mostly planted deep in the garden.']