Explanation

Nitrogen is a key component of amino acids, the building blocks of proteins.

Thus, in plants and animals, nitrogen mainly exists in the form of proteins.

Explanation

The following table provides the botanical names for a variety of familiar plants: 

Explanation

Caffeine occurs naturally in the tea plant,

Camellia sinensis, so all brewed tea contains some caffeine. 

Tea leaves contain 3.5% caffeine,

while

Coffee beans have 1.1–2.2%.

Explanation

Spirogyra, Volvox, and Chlamydomonas are all examples of green algae.

These organisms are known for containing chlorophyll, the primary pigment for photosynthesis, and are simple, aquatic, and autotrophic. 

Explanation

The tissue found between the upper and lower epidermis of a leaf is known as the mesophyll. 

In most plants, the mesophyll is composed of two distinct layers: 

Palisade mesophyll:

Located just below the upper epidermis, this layer consists of tightly packed, column-shaped cells that are rich in chloroplasts.

It is the primary site of photosynthesis.

Spongy mesophyll:

Located below the palisade layer, this tissue has irregularly shaped cells with large air spaces between them.

These spaces allow for the circulation of carbon dioxide, oxygen, and water vapor.