-Aqsa, Subject Matter Expert at Edumarz.
Solution: Tissues that are composed of only one type of cell are called Simple tissue. There are three types of simple tissues:
Parenchyma – They are thin-walled living cells. Their cell wall is made up of cellulose, hemicellulose, and pectin. They are more or less spherical nut also may be polyhedral. Young parenchymatous cells are loosely arranged with intracellular space between. Mature parenchymatous cells remain tightly packed and lack intercellular spaces. Photosynthetic parenchymatous cells have chloroplast, Non-photosynthetic parenchyma cells possess leucoplast. Storage parenchyma stores starch grains, inulin crystals, and raphides.
Collenchyma – It is a mechanical tissue and consists of living cells. It retains protoplasm even at maturity. Collenchyma cells may be polygonal, spherical, or elongated with pointed or rounded ends in shape. The cell wall remains unevenly thickened because of the deposition of pectin and hemicelluloses. Collenchyma may or may not leave intercellular spaces. These may contain chloroplast and carry out photosynthesis.
Sclerenchyma – The cell walls are long or short, narrow, thick-walled, and lignified. Sclerenchyma is dead cells and does not perform any metabolic function. They show different types of lignin deposition and also have pits.