Explanation

• Natural selection is a process of evolution.
• It favors traits that help organisms survive and reproduce.
• Beneficial traits become more common over generations.
• Harmful traits tend to decrease in frequency.
• It depends on environmental conditions.

Last verified on 20-05-2026

Explanation

• A population bottleneck occurs when a large population suddenly becomes very small.
• This is usually due to disasters, diseases, or environmental changes.
• Only a few individuals survive and reproduce.
• Genetic drift becomes very strong in small populations.
• It reduces genetic diversity in the population.

Last verified on 20-05-2026

Explanation

Explanation

• Meiosis is a special type of cell division in living organisms.
• It occurs in reproductive cells (germ cells).
• It reduces chromosome number from diploid (2n) to haploid (n).
• It produces genetically different cells.
• Final result is formation of gametes.

Last verified on 20-05-2026

Explanation

• A cross between two heterozygous individuals (Aa × Aa) is a monohybrid cross.
• Each parent produces two types of gametes: A and a.
• Offspring combinations are AA, Aa, Aa, and aa.
• This gives a characteristic Mendelian ratio in genotype.
• It follows simple inheritance laws proposed by Mendel.

Last verified on 20-05-2026

Explanation

• Mendel’s law of independent assortment explains how traits are inherited independently.
• It works during gamete formation (meiosis).
• Genes are inherited independently if they are not physically linked.
• This usually happens when genes are on different chromosomes.
• It can also apply when genes are far apart on the same chromosome (due to crossing over).

Last verified on 20-05-2026

Explanation

• Transition metal compounds show color due to electronic transitions.
• In copper compounds (especially Cu²⁺), d-orbitals are partially filled.
• Electrons absorb specific wavelengths of light and get excited between d-orbitals.
• The remaining reflected/transmitted light appears blue.
• This phenomenon is called d–d transition.

Last verified on 20-05-2026

Explanation

• SN2 reaction occurs in one step via backside attack.
• Steric hindrance strongly affects reaction rate.
• Less crowded substrates allow easier nucleophilic attack.
• Methyl halides have no alkyl groups blocking the carbon center.
• So they react the fastest in SN2 mechanism.

Last verified on 20-05-2026

Explanation

• Hess’s law states that total enthalpy change is independent of path.
• It depends only on initial and final states of a reaction.
• This is possible because enthalpy does not depend on the route taken.
• Such properties are called state functions.
• Therefore, enthalpy follows path independence.

Last verified on 20-05-2026

Explanation

• Ozonolysis breaks the double bond of alkenes using ozone (O₃).
• Propene has structure: CH₃–CH=CH₂.
• Double bond cleavage forms two carbonyl compounds.
• One side gives ethanal (CH₃CHO) and the other gives methanal (HCHO).
• Therefore, these are the final products after ozonolysis.

Last verified on 20-05-2026