Final answer:
The glands with fenestrated capillaries that facilitate the diffusion of hormones into the blood are known as endocrine glands. The correct option is (A).
Step-by-step explanation:
The glands you're asking about are endocrine glands. These glands are highly equipped with fenestrated capillaries, allowing for efficient diffusion of hormones into the bloodstream.
Unlike exocrine glands, which use ducts to transport secretions, endocrine glands release hormones directly into the interstitial fluid. From there, these hormones diffuse into the blood and are transported to various organs and tissues.
Well-known examples of endocrine glands include the pituitary, thyroid, parathyroid, adrenal glands, gonads, and the pancreas.