The answer is gypsum as 2 is lower than 2.5 and since the other minerals are very hard, it would cause damage to the fingernail since the fingernail's hardness is 2.5.
I am not an expert about this stuff but I think it is your second answer is correct but like I said I do not know.
The answer is vascular plants.
Vascular plants have <span>specialized tissues that can transport fluids - vascular tissue. This tissue consists of</span><span> xylem and phloem. Xylem transports water and minerals from the root to the upper parts of the plant. Phloem transports food and nutrients from the leaves, where they are produced, to the growing or storage parts of the plants. </span>
The Pteridopyhta, phylum of seedless vascular plants has about 1000 known living species, including those in the genera Lycopodium and Selaginella; the gametophyte of some of these species cannot photosynthesize, and instead uses mycorrhizae to obtain nutrients.
Explanation:
The pteridophytes, most advanced group of plant among the cryptogams i.e. seedless plants.
They are first land plants that have developed a well defined vascular system.
Ferns, horsetails etc are common members of this phylum.
