TPO阅读MINERALS AND PLANTS最后一题求助！

TPO阅读MINERALS AND PLANTS最后一题求助！
Plants need to absorb certain minerals from the soil in adequate quantities for normal growth and development.
●
●
●
Answer Choices
1.Some plants can tolerate comparatively low levels of certain minerals, but such plants are of little use for recycling nutrients back into depleted soils.
2.Mineral deficiencies in many plants can be cured by misting their roots with a nutrient solution or by transferring the plants to a soilless nutrient solution.
3.Because high concentrations of sodium chloride and other salts limit growth in most plants, much research has been done in an effort to develop salt-tolerant agricultural crops.
4.when plants do not absorb sufficient amounts of essential minerals, characteristic abnormalities result.
5.Though beneficial in lower levels, high levels of salts, other minerals, and heavy metals can be harmful to plants.
6.Some plants are able to accumulate extremely high levels of certain minerals and thus can be used to clean up soils contaminated with toxic levels of these minerals.
Research has shown that certain minerals are required by plants for normal growth and development The soil is the source of these minerals which are absorbed by the plant with the water from the soil Even nitrogen, which is a gas in its elemental state, is normally absorbed from the soil as nitrate ions Some soils are notoriously deficient in micro nutrients and are therefore unable to support most plant life So-called serpentine soils, for example, are deficient in calcium, and 【only plants able to tolerate low levels of this mineral can survive In modern agriculture, mineral depletion of soils is a major concern, since harvesting crops interrupts the recycling of nutrients back to the soil.】
这里为什么1.不对呢，1.不就是文中第一段【】里面的那个意思吗？很不解为什么1.不对~~请大侠帮忙解析一下吧！