<span>The answer is to control the crossing of the traits.
The idea of preventing plants from self-pollinating is to control the crossing of the traits. If plants were self-pollinating, he could not know if the traits are inherited from the same plant or from the other. By preventing this, he could cross parents with known phenotype and that way learn about crossing process and inheriting process.</span>
In the adults, the growth rate slows with age. The healing mechanism of the different cells if damaged is different than that of the younger ones. If a cartilage is damage in the adults, the chondrocytes which are still surviving secrete more extracellular matrix in order to heal the damaged cartilage. The chondrocytes cells are present in the cartilage, and they function to maintain the cellular matrix of the cartilage.
A biodiversity
Hope this helps