Explanation

Galaxies are the basic building blocks of the universe, consisting of stars, gas, dust, and dark matter.

The universe contains billions of galaxies, each with millions or billions of stars.

Explanation

لفظ "ریس" کا مطلب دوڑ ہوتا ہے، جو ایک مقابلہ ہوتا ہے جس میں دو یا زیادہ افراد تیز ترین رفتار سے دوڑتے ہیں۔

یہ عموماً جسمانی طاقت یا صلاحیت کا مقابلہ ہوتا ہے۔

Explanation

Each refers to individual members of a group without specifying them, making it an indefinite pronoun.

It is used to emphasize every single person in the group ("each of the men").

Explanation

Given the direct relation between time and water pulled:

Let's find the rate of water pulled per minute:

600 liters / 45 minutes = 40/3 liters per minute

In one hour (60 minutes):

Water pulled = (40/3) * 60

= 40 * 20

= 800 liters

Explanation

The preposition "in" indicates something is inside.

بلی جھاڑی میں چھپ رئی ہے۔

"In" is used when something is enclosed or surrounded by something else.

Explanation

Tungsten is commonly used as the target material in X-ray tubes due to its high atomic number and ability to withstand the high heat generated during X-ray production.

Its properties make it efficient in producing X-rays.

Explanation

Let's calculate what needs to be added:

(7 + 2a - a² + 4a³) - (2a³ + a² - 3a - 1)

= 7 + 2a - a² + 4a³ - 2a³ - a² + 3a + 1

= 2a³ - 2a² + 5a + 8

Explanation

A good topic sentence introduces a general idea; this sentence is too specific and personal.

It doesn't set up a broad theme for a paragraph like a proper topic sentence should.

Explanation

In conditional sentences, "shall" is used with "I" and "we" to express future actions.

It is used here to indicate what will happen if the condition (rain) occurs.

Explanation

A society is a collection of individuals who have organized themselves into a distinct group, typically sharing common laws, institutions, and cultural practices.

It represents a broader structure than a community or family, encompassing a larger group of people with shared norms.