Answer: C) DNA replication Explanation: S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease.

Answer: A) Aurora australis Explanation: Polar lights (aurora polaris) are a natural phenomenon found in both the northern and southern hemispheres that can be truly awe inspiring. Northern lights are also called by their scientific name, aurora borealis, and Southern lights are called aurora australis.

Answer: B) Africa Explanation: We know that, there are 7 continents in the world. They are : Asia, Africa, Australia, North America, South America, Europe and Antarctica.   Africa - 53 countries Asia - 48 countries Europe - 45 countries Antarctica - 0 countries   Hence, the continent Africa has most number of countries with 53 countries and in second place Asia has 48 , third Europe has 45 countries.

Answer: D) increase the alkalinity of the soil Explanation: Lime is sometimes applied to soil in order to increase the acidity of the soil.

Answer: D) All the above Explanation:    1) SO2                  2) CH2Cl2                3) PCl3 How to check the given molecules are polar or non polar : If the electronegativity of the two bonded atoms are different then the bond is polar. Although, some molecules contain polar bonds, the molecule may be non-polar. If the polarity of all the bonds present in the molecule are cancel each other then molecule is non-polar.   In the given options, SO2  is polar because the dipole moments on the O do not cancel. PCl3  is polar because the P-Cl bonds do not cancel out. CH2Cl2  polar because the C-Cl bonds do not cancel.   Hence, in brief, Polar molecules are molecules with net dipole due to the presence of partial positive and partial negative charge. For example, water is a polar molecule that has partial positive and partial negative charge on it. CO2 is a non polar compound.   Therefore, all the given options SO2, CH2Cl2 and PCl3 are Polar molecules.

Answer: A) TRUE Explanation: True, Air is a Mixture. Air is considered as mixture for the following reasons ; 1. Air can be separated into its components like N2, O2 , Argon and CO2 by the process of fractional distillation of liquid air. 2. Air shows the properties of all the gases present in the atmosphere. For example : Oxygen is good Supporter of combustion. Hence air also is good supporter of combustion. 3. Air does not have a fixed formula. 4. Air has a variable composition because air at different places contains different amount of gases. 5. Heat or Light energy is neither absorbed nor released when air is prepared physical by mixing required amount of gases . 6. Mixture does have fixed boiling Point. It holds good in case of liquid air.

Answer: B) Rani Lakshmi Bai Explanation:

Answer: D) Mandalams, Nadu,Kurram & Valanadu Explanation: