Explanation-1

NASA’s Cassini probe has detected an unusual wobble in the rotation of Mimas, Saturn’s smallest moon. Using a computer model to study Mimas’s gravitational interactions with Saturn and tidal forces, geophysicist Alyssa Rhoden and colleagues have proposed that this wobble could be due to a liquid ocean moving beneath the moon’s icy surface. The researchers believe other moons should be examined to see if they too might have oceans hidden beneath their surfaces.

Which choice best states the main idea of the text?

A) Rhoden and colleagues were the first to confirm that several of Saturn’s moons contain hidden oceans.

B) Research has failed to identify signs that there is an ocean hidden beneath the surface of Mimas.

C) Rhoden and colleagues created a new computer model that identifies moons with hidden oceans without needing to analyze the moons’ rotation.

D) Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.

Explanation-2

Shimmering is a collective defense behavior that researchers have observed in giant honeybee colonies. When shimmering, different groups of bees flip their bodies up and down in what looks like waves. This defense is initiated when hornets hover near a colony, serving to deter the hornets from approaching the bees. Researchers hypothesize that this behavior is a specialized defense response to hornets, as it is not observed when other, larger predators approach the colony.

Which choice best states the main idea of the text?

A) Researchers are unsure how giant honeybees defend against predators larger than hornets.

B) Researchers think that shimmering in giant honeybees is a specific defense against hornets.

C) Hornets are known to be the main predator of giant honeybees.

D) Several different species of insects use shimmering to defend against hornets.

Explanation-3

Oluwaseyi Moejoh cofounded U-recycle Initiative Africa when she was only a teenager. Moejoh and her team founded the organization to teach young people how their actions affect the environment and why recycling is important. For example, the organization put on an exhibit of art made using recycled materials.

According to the text, what is one reason Moejoh and others founded U-recycle Initiative Africa?

A) To bring attention to overlooked African artists

B) To teach young people why recycling is important

C) To help adults gain important outdoor skills

D) To give teenagers advice about starting businesses

Explanation-4

The following text is adapted from Edith Nesbit’s 1906 novel The Railway Children.

Mother did not spend all her time in paying dull [visits] to dull ladies, and sitting dully at home waiting for dull ladies to pay [visits] to her. She was almost always there, ready to play with the children, and read to them, and help them to do their home-lessons. Besides this she used to write stories for them while they were at school, and read them aloud after tea, and she always made up funny pieces of poetry for their birthdays and for other great occasions. According to the text,

what is true about Mother?

A) She wishes that more ladies would visit her.

B) Birthdays are her favorite special occasion.

C) She creates stories and poems for her children.

D) Reading to her children is her favorite activity.

Explanation-5

In 2014, Amelia Quon and her team at NASA set out to build a helicopter capable of flying on Mars. Because Mars’s atmosphere is only one percent as dense as Earth’s, the air of Mars would not provide enough resistance to the rotating blades of a standard helicopter for the aircraft to stay aloft. For five years, Quon’s team tested designs in a lab that mimicked Mars’s atmospheric conditions. The craft the team ultimately designed can fly on Mars because its blades are longer and rotate faster than those of a helicopter of the same size built for Earth.

According to the text, why would a helicopter built for Earth be unable to fly on Mars?

A) Because Mars and Earth have different atmospheric conditions

B) Because the blades of helicopters built for Earth are too large to work on Mars

C) Because the gravity of Mars is much weaker than the gravity of Earth

D) Because helicopters built for Earth are too small to handle the conditions on Mars