How does pollen tube grow through a solid style?

How does an aster form?

How does leech respire?

What is semi solid style?

Assertion : Self-incompatibility is a genetic mechanism which prevents self-pollination and thereby fertilisation by inhibiting either pollen germination or pollen tube growth in the pistil. Reason : In gametophytic self-incompatibility, the incompatibility reaction is determined by the genotype of the sporophytic tissue of the plant from which the pollen is derived.

If electrical conductivity is found to be same in all directions through a solid the substance is "__________" solid and the property is called "____________"

How does soil originate?