Chemical weathering is what happens when rocks are broken down and chemically altered.

Chemical weathering is the breakdown of rocks by chemical reactions. Chemical weathering involves changes in the chemical composition of the existing rock to form new rock. Some examples of chemical weathering are hydrolysis, oxidation, carbonation, dissolution, etc.

As the frequency of sound is higher, women have shriller voices than men.

The shrillness or pitch of a sound is determined by its frequency. The higher the pitch shriller the voice. As the sounds produced by vocal cords of women are higher than men so women have shriller voices than men. Because their vocal cord is of smaller size. As their vocal cord is more stretched than men's.

The basic unit of the nervous system is the Neurons.

The neuron is a single nerve cell, and you have billions of them.

There are three basic types of neurons::

1. Association,

2. Afferent  and

3. Efferent.

The association neurons comprise the central nervous system (CNS) that is the brain and spinal cord.

The afferent neurons are also known as the sensory neurons, they bring the stimuli from the sensors (e.g., skin, eyes, ears) to the CNS.

The efferent neurons are also known as motor neurons, they bring the responses from the brain to the muscles and the glands.

The amount of water vapor ranges from a trace amount up to 4% of the mass of air. Water vapor exists as an invisible gas in the air.

The amount of water vapor in the air is called absolute humidity. The amount of water vapor in the air as compared with the amount of water that the air could hold is called relative humidity.

The maximum amount of water vapor that can be in the air depends on the air temperature.

C2H6O is a Non-electrolyte.

An electrolyte is a compound that conducts an electric current when it is in an aqueous solution or melted. In order to conduct a current, a substance must contain mobile ions that can move from one electrode to the other. All ionic compounds are electrolytes. When ionic compounds dissolve, they break apart into ions which are then able to conduct a current ( conductivity ). Even insoluble ionic compounds such as CaCO 3 are electrolytes because they can conduct a current in the molten (melted) state.

A nonelectrolyte is a compound that does not conduct an electric current in either aqueous solution or in the molten state. Many molecular compounds, such as sugar or ethanol, are nonelectrolytes. When these compounds dissolve in water, they do not produce ions.

Electrolytes are of 3 types ---- Strong Electrolytes, Weak Electrolytes and Non Electrolytes.

Strong Electrolytes ---- Compounds which completely dissolves. ( NaCl, Na2Co3, HCl )

Weak Electrolytes ----- Compounds which do not completely dissolves.

Non Electrolytes ------ Compounds which do not dissolves at all.

Given equation can be written as

$$\begin{gathered} 215 x 103 + ? = 24 \\ => 14 + ? = 24 \\ => ? = 24 - 14 \\ => ? = 10 \end{gathered}$$

Pinctada vulgaris is a bivalve from which pearl is obtained.