Hydra and its cells
Hydra is a small multicellular organism belonging to the phylum Cnidaria. It is a simple freshwater animal that exhibits radial symmetry. Hydra's body consists of two layers: the outer epidermis and the inner gastrodermis, separated by a gel-like substance called the mesoglea.

Types of cells in Hydra
Hydra is composed of various types of cells that perform different functions. These cells include:
1. Epithelio-muscular cells: These cells are found in the outer epidermis and possess contractile properties. They are responsible for the movement and contraction of the body.
2. Nutritive-muscular cells: These cells are located in the inner gastrodermis and are responsible for capturing and digesting prey. They have long pseudopodia that aid in engulfing food particles.
3. Sensory cells: These cells are specialized for detecting stimuli from the environment. They play a role in the hydra's response to light, touch, and chemical signals.

Pseudopodia and flagella in Hydra
Pseudopodia are temporary extensions of the cell membrane that assist in movement and capturing prey. They are commonly observed in amoeboid cells and in certain types of cells in hydra, such as the nutritive-muscular cells. These cells extend their pseudopodia to engulf and ingest food particles.

Flagella, on the other hand, are whip-like structures that are involved in cell motility. They are composed of microtubules and are responsible for the movement of certain cells, such as sperm cells. However, flagella are not present in hydra cells.

Explanation of the correct answer
The correct answer to the given question is option 'C', which states that the nutritive-muscular cells in Hydra possess pseudopodia. This is because these cells are responsible for capturing and digesting prey, and the presence of pseudopodia aids in the engulfment of food particles. The other options, such as secretory cells, epithelio-muscular cells, and sensory cells, do not possess pseudopodia or flagella.

In conclusion, the nutritive-muscular cells in Hydra have pseudopodia, which are essential for their feeding process. Understanding the different types of cells and their functions in Hydra helps in comprehending the organization and physiology of this simple multicellular organism.

It is fact