BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The pollen tubes grow as fast as possible through the stigma tissue towards the egg cells where they release two sperm cells for fertilization.

Detailed explanation-2: -Pollination occurs when pollen is transferred to a receptive surface, known as the stigma, of the carpel. This pollen will then germinate and produce a pollen tube that grows down the style, which connects the stigma to the ovary, to the ovule(s).

Detailed explanation-3: -Final answer: Growth of pollen tube towards ovule is called Phototropism.

Detailed explanation-4: -Fertilization of flowers by pollen is achieved because the ovary release chemicals that produce a positive chemotropic response from the developing pollen tube. The growth of pollen tubes towards the ovule is an example of chemotropism.