Explanation

When an object is placed between F (focus) and 2F in a convex lens, the image is formed beyond 2F.

The image is real, inverted, and magnified because light rays converge beyond twice the focal length.

Explanation

Volleyball was originally called "Mintonette" when it was invented by William G. Morgan in 1895.

The name was later changed to volleyball as the game involved volleying the ball over the net.

Explanation

Explanation

The complement of a null set (∅) includes all elements of the universal set (U).

Since ∅ contains nothing, its complement is everything in U, so ∅' = U.

Explanation

The sentence contains "not", which makes it a negative sentence.

It is in the present perfect continuous tense, indicating an action that hasn’t happened since 2007.

Explanation

Centrioles play a key role in cell division by organizing spindle fibers that separate chromosomes.

They are found in animal cells.

They help in the formation of the mitotic spindle during mitosis.

Explanation

Given x = -1 and y = -3:

Let's evaluate the expression 5y² - 2(x² - 4xy) - 5y:

1. Calculate 5y² = 5(-3)² = 5(9) = 45

2. Calculate x² = (-1)² = 1

3. Calculate 4xy = 4(-1)(-3) = 12

4. Calculate x² - 4xy = 1 - 12 = -11

5. Calculate -2(x² - 4xy) = -2(-11) = 22

6. Calculate -5y = -5(-3) = 15

Now, combine the results:

5y² - 2(x² - 4xy) - 5y = 45 + 22 + 15

= 82

Explanation

A chord is a line segment that connects two points on a circle.

If the chord passes through the center, it is called the diameter.

Explanation

School, Teacher, and Playground are naming words (nouns).

Slowly is an adverb – it tells how something is done, not a name of a person, place, or thing.

Explanation

The Soviet Union suffered approximately 50,000 military casualties during their occupation of Afghanistan (1979–1989).

These heavy losses, along with economic strain and Afghan resistance, contributed to their withdrawal in 1989.