What is a tissue?
A group of cells that are similar in structure and/or work together to achieve a particular function forms a tissue. For example phloem, blood etc.
How are simple tissues different from complex tissues?
Simple tissues are made of one type of cells which coordinate to perform a common function. For example parenchyma, epidermis etc
Complex tissues are made of more than one type of cells. All these coordinate to perform a common function. For example Vascular tissues.
How many types of elements together make xylem tissue? Name them.
Xylem formed of four types of elements. They are (i) tracheids (ii) vessels (iii) xylem parenchyma (iv) xylem phloem.
What is the utility of tissues in multi-cellular organisms?
Multi-cellular organisms show division of labour because a particular function is carried out by a cluster of cells (tissue) at a definite place in the body. The tissue is arranged and designed so as to give the highest possible efficiency of function.