Ans) The chemical substances produced in plants which control growth, development and responses in plants are called plant hormones. Example-Auxins, Gibberellins, Cytokinins and Abscisic acid.

Ans) Auxin is a plant growth hormone. When the tip of the tendril touches a support, then the auxins present on its tip move to the side of the tip which is away from the support, so due to more auxins in its tendrils away from the support, the stem grows faster.

Ans) The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body.

Ans) Hormones are chemical substances produced in the body that control and regulate the activity of certain cells or organs.

Ans) A reflex action is an involuntary and instantaneous movement in response to a stimulus. A reflex is caused by neural pathways called reflex ares which can act on an impulse before that impulse reaches the brain.

Ans) A reflex action is a rapid, automatic response to a stimulus. It does not involve any thinking. Eg. closing of eyes in response to bright light. Walking, however, is an involuntary action. It is under our conscious control. The response to the reflex action is generated at the spinal cord, whereas walking is under the control of the brain.

Ans) Reflex actions are involuntary actions and they are controlled by the spinal cord. They will thus get disrupted in case of a spinal cord injury.

1. Growth Hormone
2. Insulin

Ans)

1. Growth hormone – Regulating growth and development
2. Insulin – Regulation of blood sugar.