Final answer:
The statement is incorrect because not all plant stems grow above ground. Some plant stems, such as rhizomes or stolons, grow horizontally below the ground to facilitate reproduction and spread of the plant.
Step-by-step explanation:
The statement, "All plant stems must grow above ground," is incorrect because not all plant stems grow above ground. Some plant stems, such as rhizomes or stolons, grow horizontally below the ground. Rhizomes are horizontal stems that produce roots and shoots, while stolons are horizontal stems that grow above the ground. These structures allow plants to spread and reproduce.
For example, strawberry plants have stolons that grow above the ground and produce new plantlets at the nodes. These plantlets can then take root and establish new plants. Rhizomes can be seen in plants like ginger or bamboo, which have underground horizontal stems that produce new shoots and roots.
In conclusion, not all plant stems grow above ground. Some stems, like rhizomes and stolons, grow horizontally below the ground to facilitate reproduction and spread of the plant.