Question

Astral rays are formed of:
A. Microfilaments
B. Microtubules
C. Intermediate filaments
D. Microvilli

Answer 1

Hint: Astral rays are usually formed during the division of the cell. These are the fibre like rays that are prominent when the cell is about to divide.

Complete answer:
Astral rays as the name suggests. are star-shaped cellular components that are seen during mitosis in animals. These originate during prophase and are composed of microtubules. They have a cloud-like appearance.

Additional Information:
 Prophase in meiosis is also marked by the formation of the spindle apparatus. The spindle fibres have the following functions:
-move replicated chromosomes during early mitosis and
-pull chromatids apart in late mitosis. The spindle apparatus consists of microtubules—components of the cytoskeleton.
 Microtubules have the following characteristics :
-They are composed of α-tubulin and β-tubulin dimers.
-They are asymmetric in shape as they have a plus end and a minus end.
-The plus end is the site where microtubule growth normally occurs. The disassembly of microtubules is more frequent at the negative or the minus end. Microtubules originate from microtubule-organizing centres (MTOCs).
So, the correct answer is ‘microtubules’

Note: -MTOCs define the two poles of the spindle apparatus and produce large numbers of microtubules, whose plus ends grow outward through the cytoplasm.
-It is to be noted that astral rays are absent from plant cellular division.