What does the author say in paragraph 1 regarding most species in Earth’s history?

According to the passage, what can be learnt about passive students?

Which of the following is true, according to the passage?

The final product of the process of drying liquids that uses the first method will be ______.

Why did George Washington not live in the White House?

The word “inhabitants” in line 2 is closest meaning to: .........

The word "excruciating" in the last paragraph means ________.

Different cultures follow their own special customs when a child's baby teeth fall out. In Korea, for example, they have the custom of throwing lost teeth up on the roof of a house. According to tradition, a magpie will come and take the tooth. Later, the magpie will return with a new tooth for the child. In other Asian countries, such as Japan and Vietnam, children follow a similar tradition of throwing their lost teeth onto the roofs of houses. Birds aren't the only animals thought to take lost teeth. In Mexico and Spain, tradition says a mouse takes a lost tooth and leaves some money. However, in Mongolia, dogs are responsible for taking teeth away. Dogs are highly respected in Mongolian culture and are considered guardian angels of the people. Tradition says that the new tooth will grow good and strong if the baby tooth is fed to a guardian angel. Accordingly, parents in Mongolia will put their child's lost tooth in a piece of meat and feed it to a dog. The idea of giving lost teeth to an angel or fairy is also a tradition in the West. Many children in Western countries count on the Tooth Fairy to leave money or presents in exchange for a tooth. The exact origins of the Tooth Fairy are a mystery, although the story probably began in England or Ireland centuries ago. According to tradition, a child puts a lost tooth under his or her pillow before going to bed. In the wee hours, while the child is sleeping, the Tooth Fairy takes the tooth and leaves something else under the pillow. In France, the Tooth Fairy leaves a small gift. In the United States, however, the Tooth Fairy usually leaves money. These days, the rate is $1 to $5 per tooth, adding up to a lot of money from the Tooth Fairy! 

What is the passage mainly about?

Earth is richly supplied with different types of living organisms which co-exist in their environments, forming complex, interrelated communities. Living organisms depend on one another for nutrients, shelter, and other benefits. The extinction of one species can set off a chain reaction that affects many other species, particularly if the loss occurs near the bottom of the food chain. For example, the extinction of a particular insect or plant might seem inconsequential. However, there may be fish or small animals that depend on that resource for foodstuffs. The loss can threaten the survival of these creatures and larger predators that prey upon them. Extinction can have a ripple effect that spreads throughout nature. In addition to its biological consequences, extinction poses a moral dilemma for humans, the only species capable of saving the others. The presence of humans on the planet has affected all other life forms, particularly plants and animals. Human lifestyles have proven to be incompatible with the survival of some other species. Purposeful efforts have been made to eliminate animals that prey on people, livestock, crops, or pose any threat to human livelihoods. Some wild animals have been decimated by human desire for meat, hides, fur, or other body parts with commercial value. Likewise, demand for land, water, and other natural resources has left many wild plants and animals with little to no suitable habitat. Humans have also affected nature by introducing non-native species to local areas and producing pollutants having a negative impact on the environment. The combination of these human-related effects and natural obstacles such as disease or low birthrates has proven to be too much for some species to overcome. They have no chance of survival without human help. As a result, societies have difficult choices to make about the amount of effort and money they are willing to spend to save imperiled species. Will people accept limits on their property rights, recreational activities, and means of livelihood to save a plant or an animal? Should saving such popular species as whales and dolphins take priority over saving obscure, annoying, or fearful species? Is it the responsibility of humans to save every kind of life form from disappearing, or is extinction an inevitable part of nature, in which the strong survive and the weak perish? These are some difficult questions that people face as they ponder the fate of other species living on this planet. 

What does the passage mainly discuss?

The passage supports which of the following conclusions?

The word "obscurity" could best be replaced by __________