Explanation

Teachers work closely with the principal and observe their leadership, decision-making, and management style daily.

They are in the best position to evaluate the effectiveness of the principal’s administration within the school environment.

Explanation

The domain of a relation is the set of all first elements in the ordered pairs. For the relation R: 

So, the domain of  𝑅 is {4,5,6}.

Explanation

Total marks of 28 students in Mathematics = 28 x 50 = 1400

New number of students = 28 - 8 = 20

New average of marks in Mathematics = 50 + 5 = 55

∴

Total marks of 20 students in Mathematics = 20 x 55 = 1100

∴

Total marks of 8 students who left the school = 1400 - 1100 = 300

∴

Average marks of these 8 students = 

300/8 = 37.5

Explanation

The correct sentence is: "Health is preferable to wealth."

The phrase "preferable to" is the proper way to compare two things in terms of preference.

Explanation

Line authority gives the principal the right to direct and control the work of teachers and make decisions independently.

It establishes a clear chain of command within the school organization.

Explanation

Reliability refers to the consistency of test results — if repeated trials yield the same effect or outcome, the test is considered reliable.

It ensures that the measurement tool produces stable and consistent results over time.

Explanation

"While digging" is a present participle phrase showing an action in progress.

The main action "found" is in the past simple, matching the past event.

Explanation

In the expression ln (𝑎^𝑛), 𝑛 is called the exponent.

Here’s a breakdown:

• ln denotes the natural logarithm function, which uses the base e(where e≈2.718).
• 𝑎 is the base of the exponentiation. 
• n is the exponent, which tells you how many times a is multiplied by itself.

Explanation

Bernoulli's principle states that in a flowing fluid, an increase in the fluid's speed occurs simultaneously with a decrease in pressure or potential energy

Explanation

Communication channels refer to the methods through which information is transmitted and received.

The types of communication channels typically include:

• speaking (verbal communication),
• listening (receiving and interpreting spoken information),
• reading (interpreting written text),
• writing (creating written text).

"Thinking" is not a communication channel but rather an internal cognitive process.