The bird's eye contains a nictitating membrane which is a translucent, semitransparent inner eyelid. It sweeps across the surface of the eye enabling the bird to blink without losing sight of or without blocking their view.
Birds also have two different tear glands. One type of tear gland is located along the lower eyelid while the other is located at the base of the nictitating membrane. The second tear gland lubricates the bird's eyes whenever the nictitating membrane blinks.
Explanation:

The capsid copies the host cell’s DNA is the role of the capsid play in viral reproduction.
They keep the climate of the land moderate
Plants and certain microorganisms use photosynthesis to create compounds such as carbohydrates. It's an endothermic (heat-inducing) chemical reaction that converts carbon dioxide to sugars using sunlight. Sugars are used by the cell as an energy source as well as a building block for other molecules. Photosynthesis takes place in two stages: light-dependent reactions and the Calvin cycle (light-independent reactions). Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH.