Explain in your own words with suitable examples.

A. What is meant by co-ordination?

B. How does excretion occur in human beings?

C. How is excretion in plants useful to human beings?

D. Describe the transportation system in plants.

A.

The working together of various organs of the body of an organism in a proper manner to produce appropriate reaction to the changes in the environment is called coordination. In humans, co-ordination is done by the nervous system and endocrine system. Neurons and hormones together bring growth and movements in humans.

In plants, plant hormones such as auxin, cytokinin brings coordination in plants.

B.

The primary components of the excretory system are the kidneys. The kidney is made of its units called nephron. When blood reaches the kidneys, nephrons filters blood. The useful substances are absorbed back into blood, while the waste materials are dissolved in water and removed from the body in the form of urine. With the help of ureter, urinary bladder, and urethra the urine is discharged.

C.

The excretory products of plants such as Rubber, wax, gums, resins. All these products are used by humans in their daily activities.

D.

The transport system in plants consists of xylem and phloem. Xylem transports water and Minerals from soil to the roots and from roots to the each and every plants of the plant. Phloem transports food from leaves to other parts of the plant.