A trade discount is a routine reduction from the regular, established price of a product. The use of trade discounts allows a company to vary the final price based on each customer's volume or status.

Bulliform cells are the cell that is spread among the leaf's epidermal cells. They are essential for water storage. During stress circumstances, bulliform cells assist to roll leaves to avoid water loss through transpiration. Therefore, they control the process of transpiration. Bulliform cells or the motor cells are the modified epidermal cells present on the upper surface or the adaxial surface of the monocot leaf (the grasses). They regulate the rolling of leaves to prevent the loss of water. When water is adequately present, they become turgid and keep the leaf open and exposed.

The industrial revolution starts in England and Western Europe in mid-18th Century. Its main contributions are inventions to perform work in effective and efficient manner. Some of them are,

1. Blast Furnace

It is the closed type of furnace which is capable of generating high temperatures. It is used to convert Iron into steel which is most widely used element nowadays.

2. Cotton Jenney

It is said to be a most valuable invention in the 18thcentury because it reduces time to collect cotton from cotton flowers. It is almost 300 times efficient than a normal hand.

3. Steam engine

Steam engine invented by James Watt. It revolutionizes the transport system which ultimately leads to connectivity between countries. So, different peoples, cultures and their ideas mingle to form revolutionary products and inventions to the modern world.

Fig. Steam Engine James Watt_1784

There are many other inventions that are outcomes of the industrial revolution which pave the path for modern technology.

• Economics is a social science dealing with the study of economic problems.
• Economics is a social science concerned with the production, distribution, and consumption of goods and services. It studies how individuals, businesses, governments, and nations make choices on allocating resources to satisfy their wants and needs, trying to determine how these groups should organize and coordinate efforts to achieve maximum output.
• Economics can generally be broken down into macroeconomics, which concentrates on the behavior of the aggregate economy, and microeconomics, which focuses on individual consumers and businesses.

The flow speed of a fluid can be measured using a device such as a Venturi meter or an orifice plate, which can be placed into a pipeline to reduce the diameter of the flow. For a horizontal device, the continuty plate shows that for an incompressible fluid, the reduction in diameter will cause an increase in the fluid flow speed. Subsequently Bernoulli's principle then shows that there must be a decrease in the pressure in the reduced diameter region. This phenomenon is known as the Venturi effect.

The amount of energy required to completely separate one mole of the solid ionic compound into constituent gaseous ions is known as lattice enthalpy.Lattice enthalpy is a measure of the strength of an ionic compound.

Tubules that lies more or less in the haemocoel, which open into alimentary canal.
Functions:
(a) They absorb nitrogenous waste products.
(b) They convert the nitrogenous waste products into uric add which is excreted out.