Correct Answer: D. 2/3

Correct Answer: C. regeneration

Correct Answer: B. NaNO₃(aq)

Explanation

The correct answer is D. Al(NO₃)₃(aq).

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The electrical conductivity of an aqueous solution containing a strong electrolyte depends primarily on the total concentration of ions and the magnitude of their charges.

For equimolar solutions, we look at the number of ions produced per formula unit upon complete dissociation:

• A. NH_4NO_3(aq) \rightarrow NH_4^+ + NO_3^- (produces 2 ions)

• B. NaNO_3(aq) \rightarrow Na^+ + NO_3^- (produces 2 ions)

• C. Mg(NO_3)_2(aq) \rightarrow Mg^{2+} + 2NO_3^- (produces 3 ions)

• D. Al(NO_3)_3(aq) \rightarrow Al^{3+} + 3NO_3^- (produces 4 ions)

Since Al(NO_3)_3 produces the greatest number of ions in solution (4 moles of ions per mole of solute) and contains a highly charged cation (Al^{3+}), it will have the highest electrical conductivity.

Correct Answer: B. needs in order of importance

Correct Answer: D. aggravate

Correct Answer: C. influencing government policies

Explanation

(a) Economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses.

b)(i)Opportunity cost:- This is the alternative forgone or sacrificedany time an individual makes a choice.It is the expression of cost in terms of forgone alternative.

(ii)Scale of preference:-This is the list of the wantsof an individual in order of prioritystarting with the most important to the least important.

(iii)Production possibility curve:- This is a curve that shows the possible combinations of two commodities that can be produced in an economy with the available resources and technology.

(c)(i) It helps to solve the basic economic problems of the society.

(ii) It helps in making rational choices by drawing scales of preference.

(iii) It helps to promote welfare by emphasizing opportunity cost.

(iv) It gives intellectual training on economic problems by training the mind to reason logically.

(v) It helps to predict economic trends in an economy with some level of precision.

(vi) It is useful in the study of other disciplines like engineering, business administration etc.

(vii) It helps the individual to understand the economic policies of government e.g. budget.

(viii) It helps individuals to acquire skills which are useful in various jobs and professions.

Correct Answer: A. the/the/....

Explanation

The correct answer is A. the/the/....

Here's why:

• the USA: We use the before country names that are plural or include words like States, Kingdom, Republic, Emirates (e.g., the United States, the United Kingdom, the Czech Republic, the United Arab Emirates).

• the Atlantic Ocean: We use the before the names of oceans, seas, rivers, and mountain ranges.

• Europe: We do not use an article before the names of continents, countries (most singular ones), cities, or individual islands.

Correct Answer: C. lung fish

Correct Answer: A. violence on stage