Option 1: "Dominant phase is saprophytes" - This option is incorrect. Gymnosperms are not saprophytes. They are autotrophic organisms that produce their own food through photosynthesis. They are not dependent on decaying organic matter for nutrients.

Option 2: "Vascular bundles are absent" - This is the correct answer. Gymnosperms do have vascular bundles, which are specialized tissues that transport water, minerals, and nutrients throughout the plant. Vascular tissue helps in the structural support of the plants as well.

Option 3: "Spores are heterospores" - This option is correct. Gymnosperms produce two types of spores, microspores, and megaspores. Microspores develop into male gametophytes, while megaspores develop into female gametophytes. This heterospory is a distinguishing feature of gymnosperms.

Option 4: "Flowers are absent" - This option is incorrect. Gymnosperms do not produce flowers. Instead, they produce naked seeds that are not enclosed in a protective covering like fruits.