Final answer:
A lack of vascular tissue in mosses means they cannot have true roots, stems, and leaves, essentially limiting their size and making them reliant on moist environments for survival and reproduction. The correct choice of action is C. Mosses cannot have true roots, stems, and leaves.
Step-by-step explanation:
The lack of vascular tissue in mosses affects them primarily in that they cannot have true roots, stems, and leaves. This is because vascular tissues, which include xylem and phloem, are specialized structures that transport water, nutrients, and food throughout a plant. Mosses, being nonvascular plants, are consequently limited to small sizes since they cannot efficiently move nutrients and water up a stem. They have root-like structures called rhizoids and leaf-like structures that absorb water and nutrients directly, but these structures do not have the transport capabilities of true vascular plants. As a result, mosses thrive in moist environments close to the ground, as this proximity allows for the direct absorption of water and nutrients necessary for their survival and reproduction.
It is important to note that mosses can still produce glucose by photosynthesis and do not produce flowers not due to a lack of vascular tissue, but because they are non-flowering plants and reproduce via spores. Sexual reproduction also occurs in mosses, although they are dependent on water for the movement of sperm to eggs. Thus, the correct answer to the question is that a lack of vascular tissue results in mosses not having true roots, stems, and leaves.