Main differences between Microeconomics and Macroeconomics are as under:
Microeconomics:
1. It is the study of individual economic units of an economy.
2. It deals with Individual Income, Individual prices, Individual output, etc.
3. Its central problem is price determination and allocation of resources.
4. Its main tools are demand and supply of a particular commodity/factor.
5. It helps to solve the central problem of ‘what, how and for whom’ to produce. In the economy
6. It discusses how equilibrium of a consumer, a producer or an Industry Is attained.

. Price is the main determinant of micro- economic problems.

8. Examples are: Individual Income, Individual savings, price determination of a commodity, individual firm’s output, consumer’s equilibrium.

Macroeconomics:
1. It is the study of economy as a whole and its aggregates.

2. It deals with aggregates like national Income, general price level, national output, etc.
3. Its central problem is determination of level of Income and employment.

4. Its main tools are aggregate demand and aggregate supply of the economy as a whole.

5. It helps to solve the central problem of full employment of resources in the economy.

6. It is concerned with the determination of equilibrium level of Income and employment of the economy.

7. Income is the major determinant of macroeconomic problems.

8. Examples are: National Income, national savings, general price level, aggregate demand, aggregate supply, poverty, unemployment, etc.

 
Whats does demand mean?
Demand is an economic principle referring to a consumer's desire to purchase goods and services and willingness to pay a price for a specific good or service. Holding all other factors constant, an increase in the price of a good or service will decrease the quantity demanded, and vice versa.

What is the basic law of demand?
In microeconomics, the law of demand states that, "conditional on all else being equal, as the price of a good increases (↑), quantity demanded decreases (↓); conversely, as the price of a good decreases (↓), quantity demanded increases (↑)".

What is meant by elasticity of demand?
In economics, the demand elasticity (elasticity of demand) refers to how sensitive the demand for a good is to changes in other economic variables, such as prices and consumer income. Demand elasticity is calculated as the percent change in the quantity demanded divided by a percent change in another economic variable

What is price elasticity of demand in economics?
Price elasticity of demand is an economic measure of the change in the quantity demanded or purchased of a product in relation to its price change. Expressed mathematically, it is: Price Elasticity of Demand = % Change in Quantity Demanded / % Change in Price.

The law of diminishing marginal utility explains that as a person consumes an item or a product, the satisfaction or utility that they derive from the product wanes as they consume more and more of that product. For example, an individual might buy a certain type of chocolate for a while. Soon, they may buy less and choose another type of chocolate or buy cookies instead because the satisfaction they were initially getting from the chocolate is diminishing.


In economics, the law of diminishing marginal utility states that the marginal utility of a good or service declines as its available supply increases. Economic actors devote each successive unit of the good or service towards less and less valued ends. The law of diminishing marginal utility is used to explain other economic phenomena, such as time preference.

The Law of Diminishing Marginal Utility Explained
Whenever an individual interacts with an economic good, that individual acts in a way that demonstrates the order in which they value the use of that good. Thus, the first unit that is consumed is dedicated to the individual's most valued end. The second unit is devoted to the second most valued end, and so on. In other words, the law of diminishing marginal utility postulates that when consumers go to market to purchase a commodity, they do not attach equal importance to all the commodities they buy. They will pay more for some commodities and less for others.

As another example, consider an individual on a deserted island who finds a case of bottled water that washes ashore. That person might drink the first bottle indicating that satisfying their thirst was the most important use of the water. The individual might bathe themselves with the second bottle, or they might decide to save it for later. If they save it for later, this indicates that the person values the future use of the water more than bathing today, but still less than the immediate quenching of their thirst. This is called ordinal time preference. This concept helps explain savings and investing versus current consumption and spending.