Explanation

The micro-teaching system was introduced at Stanford University in 1961.

It was developed as a method for teacher training, allowing educators to practice teaching in a controlled, small-scale environment before applying their skills in larger classrooms.

Explanation

The correct phrase is "by his will", which means according to his desire or choice.

"By" is used to show the agent or means through which something happens — here, his own will.

Explanation

The time period (T) of a simple pendulum is given by:

T ∝ √L

If the length (L) is made four times:

New time period T' ∝ √(4L)

T' ∝ 2√L

T' = 2T

The time period will become double.

Explanation

"Percent" means per hundred, so 1% = 1 ÷ 100

It can also be written as a decimal: 0.01.

Explanation

To evaluate the expression 3x + 6y + 4x, we need to combine like terms:

3x + 6y + 4x = (3x + 4x) + 6y

= 7x + 6y

So, the correct result is 7x + 6y.

Explanation

Water makes up about 70% of the cell's composition.

It is crucial for various cellular processes, including biochemical reactions and maintaining cell structure.

Explanation

Temperature differences across the Earth, due to sunlight angle and duration.

They are a major factor in creating different climates.

These variations influence air pressure, precipitation, and seasonal patterns, shaping climate zones.

Explanation

The head of a chlorophyll molecule contains a porphyrin ring with a central magnesium (Mg) atom.

This ring has four nitrogen atoms that coordinate with the magnesium, forming a stable complex essential for photosynthesis.

Explanation

Multiply the constants: 3 × 4 = 12.

Add the exponents of x: x² × x³ = x⁵, so the product is 12x⁵.

Explanation

In HNO₃ (nitric acid):

Hydrogen (H) = +1

Oxygen (O) = -2 (×3 = -6)

Let nitrogen = x

So, +1 + x + (−6) = 0

⇒ x = +5

Nitrogen has an oxidation state of +5 in HNO₃.