Astral body is a structure that appears during cell division in animal cells. It is formed of microtubules that radiate out from the centrosome towards the cell membrane. The correct answer is option 'D'.

Explanation:

Microtubules are long, thin, tube-like structures that are present in the cytoplasm of cells. They play a vital role in cell division, cell movement, and maintaining cell shape. During cell division, microtubules form the spindle fibers that pull the chromosomes apart into two new cells. The spindle fibers are attached to the centrosome, which is a small, spherical structure located near the nucleus.

During cell division, microtubules form an aster, which is a star-shaped structure that radiates out from the centrosome towards the cell membrane. The aster is also known as the astral body. The astral body helps to position the spindle fibers and the chromosomes during cell division.

In addition to their role in cell division, microtubules also play a role in intracellular transport. They act as tracks for motor proteins to move along, carrying vesicles and other cellular components to their destination.

Conclusion:

In conclusion, the astral body is formed of microtubules that radiate out from the centrosome towards the cell membrane. Microtubules play an important role in cell division and intracellular transport.

The astral body is a term used in spiritual and esoteric traditions to refer to a non-physical aspect of the human being that is believed to exist beyond the physical body. While there is no scientific evidence to support the existence of the astral body, it is often described as being composed of energy or light, and it is said to be capable of traveling outside of the physical body during certain states of consciousness, such as during meditation or near-death experiences.

However, in the context of biology, there is a different meaning to the term "astral body". In cell biology, the astral body refers to a structure that is formed during cell division, specifically during the process of mitosis. During mitosis, the cell's chromosomes are separated into two daughter cells, and the astral body is a network of microtubules that extend from the centrosomes (structures that organize the microtubules) towards the cell's periphery.

The astral body has several important functions during mitosis, including:

1. Positioning of the spindle: The astral microtubules help to position the spindle apparatus in the center of the cell, which is important for ensuring that the chromosomes are divided equally between the two daughter cells.

2. Cell shape and polarity: The astral microtubules also help to maintain the shape and polarity of the cell during mitosis, which is important for proper cell division.

3. Cell migration: In some cells, the astral microtubules can also aid in cell migration, by providing a scaffold for the cell to move along.

In summary, the astral body in cell biology refers to a network of microtubules that form during mitosis and have several important functions in cell division and cell migration. This is different from the spiritual concept of the astral body, which is a non-physical aspect of the human being that exists beyond the physical body.