The excretory structures in animal kingdom that are associated with digestive tract areA) Nephridia B) Malpighian tubulesC) Flame cells D) Nephrons

The excretory structures in the animal kingdom that are associated with the digestive tract are Malpighian tubules (Option B). These are found in insects and other terrestrial arthropods. They are attached to the digestive tract and remove waste products from the hemolymph (the insect equivalent of blood), which are then excreted along with digestive waste.

Here's a step-by-step breakdown:

1. Nephridia (Option A) are excretory organs that filter out waste from the blood in many invertebrates, but they are not directly associated with the digestive tract.

2. Malpighian tubules (Option B) are the excretory organs of insects and other terrestrial arthropods. They are directly attached to the digestive tract and remove waste products from the hemolymph, which are then excreted along with digestive waste.

3. Flame cells (Option C) are excretory structures in flatworms, but they are not directly associated with the digestive tract.

4. Nephrons (Option D) are the functional units of the kidney in vertebrates, involved in the process of filtering blood and creating urine. They are not directly associated with the digestive tract.

So, the correct answer is B) Malpighian tubules.