Question

Short notes.
a). Root pressure.
B). Transpiration.
c). Reflex action.
d). Nerve cell. ​

Answer 1

a). ROOT PRESSURE

Root pressure is the transverse osmoticpressure within the cells of a root system that causes sap to rise through a plant stem to the leaves. Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day.

B). TRANSPIRATION

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth and metabolism. The remaining 97–99.5% is lost by transpiration and guttation

c). REFLEX ACTION

A reflex, or reflex action, is an involuntary and nearly instantaneous movement in response to a stimulus. A reflex is made possible by neural pathways called reflex arcs which can act on an impulse before that impulse reaches the brain. 

d). NERVE CELL

We can now say that- A neuron (also called neurone or nerve cell) is a cell that carries electrical impulses. Neurons are the basic units of the nervous system. Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibres.

Answer 2

A,Root pressure can transport water and dissolved mineral nutrients from rootsthrough the xylem to the tops of relatively short plants when transpiration is low or zero. The maximum root pressure measured is about 0.6 megapascals but some species never generate any root pressure.

B,Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. ... Leaf surfaces are dotted with pores called stomata, and in most plants they are more numerous on the undersides of the foliage.

C,When a receptor is stimulated,it sends a signal to the central nervous system,where the brain coordinates the response. These are rapid and and happen without us thinking. A reflex action is an automatic , rapid response to the stimulus.

D,A neuron (also called neurone or nerve cell) is a cellthat carries electrical impulses. Neurons are the basic units of the nervous system. Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibres.