Final answer:
Option (d), Land plants have evolved structural adaptations like alternation of generations, apical meristem tissue, a waxy cuticle, and cell walls with lignin to address the challenges of terrestrial life, such as water conservation, structural support, and reproduction without water.
Step-by-step explanation:
Adaptations of Land Plants
Land plants have evolved several distinct structural adaptations to survive in terrestrial environments. Unlike their aquatic ancestors, land plants needed to develop new strategies for water conservation, reproduction, structural support, and protection from UV radiation. The most significant of these adaptations include:
- Alternation of Generations: A life cycle that includes both a multi-cellular sporophyte stage, which produces spores, and a gametophyte stage, which produces gametes.
- Apical Meristem Tissue in roots and shoots that enables continuous growth.
- A waxy cuticle to minimize water loss, though it is not present in some plants like mosses.
- Cell walls with lignin that offer support for the plant body to stand upright off the ground.
These adaptations are essential for plants to manage the challenges of a land-based existence, such as desiccation, vertical growth against gravity, and reproductive strategies that do not rely on water for gamete transport. Plants such as mosses represent an intermediate stage in these adaptations, demonstrating the evolutionary progression from aquatic to terrestrial life forms.