Question

The cells absent in the gastrodermis of hydra are
A)Nutritive cells
B)Stinging cells/cnidoblasts
C)Gland cells
D)Nerve/sensory cells

Answer 1

Hint: The family cnidaria includes jellyfish sea animals and corals hydra. They all use a cell that is used to catch their prey. The cells are present on the tentacles. By using these cells Hydra used to stun animals and then kill their prey before eating them alive, like plankton, water fleas, etc.

Complete answer:
The Gastrodermis- Its structure is similar to the epidermis because the coelenteron is lined by a layer of cells. The gastrodermis is made of large columnar epithelial cells and contain unstructured flat bases.
-The cells which are on the free end give coelenteron a rough and uneven contour in a cross-section.
-About two-thirds of the wall of the body is formed by the gastrodermis. Its function is to perform digestion, as a secretary, muscular and sensory.
-Nutritive muscular, interstitial, and gland cells are the cells of the gastrodermis.

Additional Information: Nutritive cells- The nutritive cells are usually vacuolated and mostly filled with the food vacuoles. It has two flagella present on the free end of the cell. The cells of the gastrodermis in the Hydra contain green algae. Green algae Give color to the Hydra. The cells of nutritive muscular secrete digestive enzymes. This enzyme helps in the digestion of food into the coelenteron.
Gland cells -their larger end face the coelenteron and they mostly are ring-shaped. They are distributed one by one between the digestive cells. Most of the gland cells Compressed to a confined base Which expands towards the mesoglea but never reaches it.
Stinging cells- Stinging cells are present on the tentacles. it covers the outside part of their tentacles. stinging cells are also called cnidocytes. These cells help in stunting their prey because this cell tied up with the plant. The Hydra plant has a very restricted range of movement. So, with the help of tentacles i.e their stinging cells, Trapped the prey(a food source) and took it into its mouth. They usually eat plankton and water flea.

So, the correct answer is, "Stinging cells/cnidoblasts".

Note: -Instead of doing the feeding, the stinging cells also protect the animals and serve as self-defense and also for locomotion purposes
-So, the cells absent in the gastrodermis of hydra are stinging cells/cnidoblasts.