Why is zona pellucida retained around the egg till it reaches uterus?

Zona pellucida is retained for some time after fertilization. Give reasons.

Which types of telescopes are orbiting around the earth? why it is necessary to put them in space?

Which type of telescopes are orbiting around the earth? Why is it necessary to put them in space ?

How does zona pellucida of ovum help in preventing polyspermy?

What would happen if the sperm fuses with the egg before it reaches the fallopian tube?

In activity 2, why does the coin become visible once the level of water reaches a certain height?

Differentiate between Zona pellucida and Corona radiata

An elephant and a matchbox fall from a height of 200m.if they are in a state of free fall,which of them will reach the ground first and why?

Answer the following questions : Take a feather and a paper. Allow them to fall to the ground simultaneously . Which will reach the ground earlier? why?