Three features of cardiac muscles are:
→ Cardiac muscles are involuntary muscles that contract rapidly, but do not get fatigued.
→ The cells of cardiac muscles are cylindrical, branched, and uninucleate.
→ They control the contraction and relaxation of the heart.

Functions of areolar tissue:
→ It helps in supporting internal organs.
→ It helps in repairing the tissues of the skin and muscles.

Tissue is a group of cells that are similar in structure and are organized together to perform a specific task.

Xylem is composed of following elements:
→ Tracheids
→ Vessels
→ Xylem parenchyma
→ Xylem fibres

Simple tissue	Complex tissue
These tissues consist of only one type of cells.	These tissues are made up of more than one type of cells.
The cells are more or less similar in structure and perform similar functions.	Different types of cells perform different functions. For example, in the xylem tissue, tracheids help in water transport, whereas parenchyma stores food.
Three types of simple tissues in plants are parenchyma, collenchyma, and sclerenchyma.	Two types of complex permanent tissues in plants are xylem and phloem.

Parenchyma	Collenchyma	Sclerenchyma
Cell walls are relatively thin, and the cells in parenchyma tissues are loosely packed.	The cell wall is irregularly thickened at the corners, and there is very little space between the cells.	The cell walls are uniformly thickened, and there are no intercellular spaces.
The cell wall in this tissue is made up of cellulose.	Pectin and hemicellulose are the major constituents of the cell wall.	An additional layer of the cell wall composed mainly of lignin is found.

The functions of stomata are:
→ The exchange of gases (CO₂ and O₂) with the atmosphere.
→ The loss of excess water in the form of water vapour which is known as transpiration.

The three types of muscle fibres are:Striated muscles, smooth muscles (unstriated muscle fibre), and cardiac muscles.

Striated muscle fibres

Unstriated muscle fibres

Cardiac muscle fibres