An atom's structure consists of a dense, positively charged nucleus at the center, made of protons and neutrons, and negatively charged electrons orbiting the nucleus in shells or orbitals. The number of protons in the nucleus determines the element's atomic number, while a neutral atom has an equal number of protons and electrons. Electrons exist in specific energy levels, governed by quantum mechanics, and their arrangement determines the atom's chemical properties.

Adaptations of Arabian Oryx (Desert Habitat)

White body colour reflects sunlight → keeps the body cool in the desert.

Can survive many days without drinking water → gets water from plants + reduces water loss.

Body temperature can rise safely → less sweating → saves water.

Long sharp horns → protection from predators.

Wide hooves → easy to walk and run on loose desert sand.

• The human skeletal system is made of 206 bones.

• It gives the body shape and support.

• It protects important organs like the brain, heart, and lungs.

• It works with muscles to help the body move.

• Bones store minerals such as calcium.

• Bone marrow inside some bones makes blood cells.

Burning releases exothermic reaction

An exothermic reaction is a chemical or physical process that releases energy, typically as heat, light, or sound, into its surroundings.

A chemical bond is the attractive force that holds atoms, ions, or molecules together to form a compound.

An attractive force is a force that causes objects or particles to move toward each other.

Combustion is a rapid chemical reaction between a substance, called a fuel, and an oxidant, usually oxygen, that releases energy as heat and light, often with a flame.

An oxidant, also called an oxidizing agent, is a chemical substance that accepts electrons from another substance during a chemical reaction.

1. air pollution

air pollution happens when harmful gases dust or smoke mix with the air we breathe

2. water pollution

water pollution happens when dirty or harmful substances mix into water bodies like rivers lakes and oceans

3. land pollution

Land pollution happens when the ground is covered or filled with harmful waste

1. Meaning:Variation means small difference in a species.

   
   

2. Example: All humans are the same species, but we are differ in skin type, hair colour, height etc.

   
   

3. Cause: Variation happens because of the genes.

   
   

4. Types:

   1. Inherited variantion

   2. Environmental Variation

      
      

What are species ?

ANS: Scientist group living organisms in to diffrent kinds , called species .

. A species is a group of organisms that all share the same characterastics .

key word

. classification

. It shows how every type of organism we know of is connected to all the others .

Non-metals are elements that mostly lack the properties of metals and can exist as gases, liquids, or solids. They are usually dull and not shiny, except for some like iodine. Non-metals are generally poor conductors of heat and electricity, with an exception being graphite, a form of carbon that can conduct electricity. Their melting points tend to be lower than metals, and they are brittle, meaning they break easily and cannot be bent or shaped. Chemically, non-metals have high electronegativity and ionization energy, so they tend to gain electrons in reactions, forming negative ions and acidic oxides when combined with oxygen. Non-metals include elements such as carbon, sulfur, iodine, oxygen, and hydrogen. Some non-metals, like carbon, show allotropy, existing in different forms with distinct physical properties, such as diamond and graphite. Non-metals do not exhibit malleability or ductility, unlike metals, and they do not produce metallic bonding which accounts for…