Bioremediation aims to clean up contaminated environments using microorganisms, making option 'To clean up contaminated environments' the correct answer.

The main goal of conservation biology is to protect endangered species and their habitats.

Family planning allows couples to make informed decisions about the number and spacing of their children, promoting reproductive health.

Sustainable development aims to meet the needs of the present without compromising the ability of future generations to meet their own needs, balancing economic growth with environmental protection.

Quantization in atomic physics means that energy levels in an atom are discrete, not continuous.

Plastic pollution leads to ingestion and entanglement of marine animals, causing injury and death.

The Rutherford model fails to explain why electrons do not spiral into the nucleus, thus not accounting for atomic stability.

The main method of hydrogen production in the industry is steam reforming of natural gas.

In the laboratory, hydrogen is commonly produced by the reaction of metals (like zinc) with acids.

HIV is primarily transmitted through sexual contact.

Polystyrene is produced from the polymerization of styrene monomers.

Birds and reptiles primarily excrete uric acid, which is less toxic and conserves water compared to urea.

Reptiles and birds primarily excrete uric acid, which is less toxic and conserves water.

When aluminum reacts with hydrochloric acid, hydrogen gas (H2) is produced along with aluminum chloride (AlCl3).

When hydrogen reacts with oxygen, the main product formed is water (H2O).

The fusion of hydrogen nuclei primarily produces helium, along with a release of energy.

The main product of the reaction between aluminum and hydrochloric acid is hydrogen gas (H2).

The main products of the neutralization reaction between an acid and a base are salt and water.

The reaction of 1-bromo-2-methylpropane with KOH in ethanol leads to the formation of 2-methylpropene through an elimination reaction.

The thermal decomposition of ammonium dichromate produces chromium(III) oxide (Cr2O3) as the main product.

Alcoholic KOH promotes elimination reactions, leading to the formation of propene from 1-bromopropane.

The reaction of 1-bromopropane with magnesium in dry ether forms the Grignard reagent, propylmagnesium bromide.

Alcoholic KOH promotes elimination reactions, leading to the formation of propene from 1-chloropropane.

Excess alcoholic KOH promotes elimination reactions, leading to the formation of propene from 1-chloropropane.

When aluminum reacts with hydrochloric acid, hydrogen gas (H2) is produced along with aluminum chloride (AlCl3).

The main product of the reaction between an amine and a carbonyl compound is an amide.

The main product of the reaction between an amine and a haloalkane is a quaternary ammonium salt.

The reaction of ethene with water in the presence of an acid yields ethanol.

When hydrogen reacts with oxygen, the main product formed is water (H2O).

Sodium borohydride reduces propan-2-one to propan-2-ol, which is a secondary alcohol.