Correct Answer: C. tin and columbite

Correct Answer: C. decisions are effected with the consent of citizens

Correct Answer: D. ±2

Correct Answer: B) Combustion

Explanation

An alkanoic acid, also known as a carboxylic acid, is an organic compound containing a carboxyl group (-COOH) attached to an alkyl group. These compounds have a general formula of R-COOH, where R represents an alkyl group.

Among the given options, alkanoic acids cannot undergocombustion reactions. Combustion reactions are characterized by the reaction of a substance with oxygen, producing heat and light energy along with products like carbon dioxide and water. Alkanoic acids have high oxygen content, which makes them less reactive in combustion reactions compared to hydrocarbons like alkanes, alkenes, and alkynes.

On the other hand, alkanoic acids can undergo the following types of reactions:

Oxidation: Alkanoic acids can be oxidized to form carbon dioxide and water. This reaction usually requires the presence of strong oxidizing agents like potassium permanganate (KMnO₄) or potassium dichromate (K₂Cr₂O₇).

Decomposition: Alkanoic acids can undergo thermal decomposition, where they break down into simpler compounds when heated. For example, ethanoic acid (CH₃COOH) can decompose into methane (CH₄) and carbon dioxide (CO₂) when heated.

Esterification: Alkanoic acids can react with alcohols in the presence of an acid catalyst to form esters and water. This is known as esterification. For example, ethanoic acid (CH₃COOH) can react with ethanol (CH₃CH₂OH) to form ethyl ethanoate (CH₃COOCH₂CH₃) and water (H₂O).

Correct Answer: C) Transpiration

Explanation

Excessive loss of water in plants is known as transpiration. Transpiration is the process in which water evaporates from the leaves of plants and exits through small pores called stomata. This process helps plants to absorb nutrients from the soil and distribute them throughout the plant. Transpiration is an important process in plant growth and survival, but excessive loss of water can lead to dehydration and wilting. Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration through a semi-permeable membrane. Osmoregulation is the process by which living organisms maintain the balance of water and salt concentrations in their bodies. Excretion is the process of removing waste products from the body. None of these options describe excessive loss of water in plants, which is why the correct answer is transpiration. Understanding transpiration is important for students studying photosynthesis and plant biology. Plants need to maintain a balance between water loss and nutrient absorption, and transpiration plays a key role in this process. To learn more about this, please read the relevant sections of the recommended textbooks.

Correct Answer: C) re-insurance

Explanation

Subrogation, Option A, refers to the process by which an insurance company seeks reimbursement from a third party for a claim it has paid out. This is not the same as the practice described in the question.

Contribution, Option B, is the sharing of a loss or claim by multiple insurers who have covered the same risk. This is not the same as the practice described in the question.

Indemnity, Option D, refers to the principle of compensation for loss or damage. This is not the same as the practice described in the question.

So, the correct answer to the question is Option C: re-insurance.

Correct Answer: A. improved social and medical facilities

Explanation

The provision of modern and improved medical and social facilities to area tends to attract more population concentration to another. Other options are wrong because the government being stable does not determine population growth, social amenities provided by the government is the only factor that can make the population growth low, either rainfall or not, people will migrate and reproduce. The agricultural system practical in an area also does not determine rapid population growth. Either mono-cropping or mixed farming is practiced population will always grow.

Correct Answer: A. inspiration

Correct Answer: C. \(\frac{x-7}{x^2 - 1}\)

Explanation

\(\frac{4}{x+1}-\frac{3}{x-1} \\

=\frac{4x - 4 - 3x - 3}{(x+1)(x-1)}=\frac{x-7}{x^2 - 1}\)

Correct Answer: D. Umar b. Abdul Aziz