Magnets are able to place a force on certain materials. This force is called a magnetic force. The force a magnet exerts is a little different from the forces you may normally think about. You exert a force on a book when you lift it. You also exert a force on the pedals of your bicycle. In both those cases, those forces cause a change. The change you see in both these cases is called motion. Magnets, too, can produce change. They can produce motion just like you do. Unlike you, magnets do not have to touch something to exert a force. A magnetic force is exerted over a distance. Thats right, a magnet can push or pull certain items without ever touching them. Thats how the maglev train works. Do you know another type of force that does not require objects to touch? These forces are known as non-contact forces. Another type of non-contact force you may be familiar with is gravity. Gravity too can cause changes in motion. Gravity holds our moon in orbit without touching it.

Question: "How do magnets exert force?"

Response: "A magnetic force is exerted over a distance"

A: yes

The one person who, by his interference, could have settled all doubts was debarred by circumstances from interfering in the matter. Wykham Delandre had quarrelled with his sister--or perhaps it was that she had quarrelled with him--and they were on terms not merely of armed neutrality but of bitter hatred. The quarrel had been antecedent to Margaret going to Brent's Rock. She and Wykham had almost come to blows. There had certainly been threats on one side and on the other; and in the end Wykham, overcome with passion, had ordered his sister to leave his house. She had risen straightway, and, without waiting to pack up even her own personal belongings, had walked out of the house. On the threshold she had paused for a moment to hurl a bitter threat at Wykham that he would rue in shame and despair to the last hour of his life his act of that day. Some weeks had since passed; and it was understood in the neighbourhood that Margaret had gone to London, when she suddenly appeared driving out with Geoffrey Brent, and the entire neighbourhood knew before nightfall that she had taken up her abode at the Rock. It was no subject of surprise that Brent had come back unexpectedly, for such was his usual custom. Even his own servants never knew when to expect him, for there was a private door, of which he alone had the key, by which he sometimes entered without anyone in the house being aware of his coming. This was his usual method of appearing after a long absence.

Question: "What is Brent's usual method of coming home after a long absence?"

Response: "The quarrel had been antecedent to Margaret going to Brent's Rock"

A: no

When land is cleared, habitats are lost. It may be cleared for agriculture. It may also be used for building new homes or businesses. Within the past 100 years, the amount of land used for agriculture has almost doubled. Land used for grazing cattle has more than doubled. Many wetlands have also been lost to agriculture. The U.S. has lost almost all the natural tall-grass prairies. Thee areas of tall thick grass have virtually disappeared. These areas of land had thick fertile soil. Their grasses had very deep root systems. These deep and thick roots reduced the amount of soil erosion. They also were home to many plants and animals. Prairies were wonderful places. They were home to colorful flowers, prairie dogs, and herds of bison.

Question: "What reduced the amount of soil erosion in grass?"

Response: "Shallow roots"

A:
no