Final answer:
Pollen grains do not have air bladders; they are male gametophytes with protective cell walls containing sporopollenin that allows them to be transported by various means.
Step-by-step explanation:
False. Pollen grains do not possess air bladders. They are male gametophytes containing a few cells, and they are protected by cell walls that contain sporopollenin, a complex substance that helps them resist desiccation and facilitates their transport by wind, water, or animals. In some cases, like gymnosperms such as cycads and Ginkgo, the sperm are motile and use flagella to swim to the egg, but this movement occurs after they are released from the pollen grain. Pollen grains exhibit a variety of shapes and structures, as seen in different plant species under a microscope, but air bladders are not a feature of pollen.