If a reaction takes 50 seconds at 25 ℃, then at 50 ℃ the time for the reaction in seconds is likely to be about:

Instructions: Choose from the four suggested answers the word which is closest to OPPOSITE in meaning to the underlined word.

As a result of the need for trained staff, the firm had to dismiss several workers.

__________ are used in specialized fields such as engineering and drafting for outputting large-format drawings.

Which of the following words BEST describes a quadrilateral with all its sides equal?

Acid soils can be neutralised by adding:

Which of the following social issues are associated with the use of illegal drugs by adolescents?

1. Criminal activity
2. Indiscipline
3. Early marriage
4. Poverty

Which one of the following gases is considerably heavier than air?

0.0039 × 10^-2 in scientific notation is

Which of the following substances contains the elements carbon, hydrogen, oxygen and nitrogen?
Ⅰ DNA
Ⅱ carbohydrates
Ⅲ lipids
Ⅳ proteins

The lowest and the highest frequencies a typical young person′s ear can detect are approximately:

If a flask containing marble and acid is placed on a balance, the mass decreases steadily with time, which means that:

All of these are ordered crystalline structures EXCEPT for:

Which one of the following is NOT a vector quantity?

We do not see an object if rays of light from it are focussed on the blind spot because:

The nucleus of a carbon atom has six protons and eight neutrons.Which one of the following describes it?

A molecule of ethene can be described as all of these EXCEPT for:

The biceps and triceps are an antagonistic pair of muscles because:

Which of the following characteristics MUST ALL formal groups possess?

1. Membership requirements
2. Code of conduct
3. Specific objectives
4. Elected leaders

The major plant nutrients written as NPK refer to phosphorus, nitrogen and:

The expression (3x - 2)(x + 1) =