Define chalazogamy and ornithophily .

Explanation

### Step-by-Step Solution:

1. **Definition of Ornithophily**:
- Ornithophily refers to the type of pollination that occurs when birds act as the agents of pollination. In this process, pollen grains (which contain male gametes) are transferred from the anther (the male part of the flower) to the stigma (the female part of the flower) with the help of birds. This is a specific form of biotic pollination where birds facilitate the fertilization process in flowering plants.

2. **Definition of Chalazogamy**:
- Chalazogamy is a specific type of fertilization process in flowering plants. In this process, the pollen tube, which carries the male gamete, penetrates the ovule through a region called the chalaza. The chalaza is part of the ovule where the integument (the protective layer) is located. This entry of the pollen tube through the chalaza allows the male gamete to reach the female gamete within the embryo sac for fertilization.

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