Answer the following question given this paragraph: The aim of basic science is to discover new knowledge. It leads to a better understanding of the natural world. It doesn't necessarily have any practical use. An example of basic research in life science is studying how yeast cells grow and divide. Yeasts are single-celled organisms that are easy to study. By studying yeast cells, life scientists discovered the series of events called the cell cycle. The cell cycle works not only in yeasts but in all other organisms with similar cells. Therefore, this basic research made a major contribution to our understanding of living things. Watch the following animation to learn more about the basic yeast research and the cell cycle. You can also see yeast cells dividing. Q: What kind of organisms are yeasts? Choices: - bacteria - viruses - protozoa - single-celled A:
single-celled
Answer the following question given this paragraph: There is a lot of volcanic activity at divergent plate boundaries in the oceans. As the plates pull away from each other, they create deep fissures. Molten lava erupts through these cracks. The East Pacific Rise is a divergent plate boundary in the Pacific Ocean ( Figure below ). The Mid-Atlantic Ridge is a divergent plate boundary in the Atlantic Ocean. Q: In what ocean is the mid-atlantic ridge located? Choices: - indian ocean - pacific ocean - arctic ocean - atlantic ocean A:
atlantic ocean
Q: Answer the following question given this paragraph: Cilia and flagella are extensions of the plasma membrane. Q: Cilia and flagella are extensions of what? Choices: - cell nucleus - protoplasm - cell wall - plasma membrane A:
A: plasma membrane
Question: Answer the following question given this paragraph: Near-Earth asteroids have orbits that cross Earth's orbit. This means that they can collide with Earth. There are over 4,500 known near-Earth asteroids. Small asteroids do sometimes collide with Earth. An asteroid about 510 m in diameter hits about once per year. Five hundred to a thousand of the known near-Earth asteroids are much bigger. They are over 1 kilometer in diameter. When large asteroids hit Earth in the past, many organisms died. At times, many species became extinct. Astronomers keep looking for near-Earth asteroids. They hope to predict a possible collision early so they can to try to stop it. Q: In the past, what colliding with planet earth has caused many organisms to die off? Choices: - acid rain - meteorites - the Sun - asteroids A:
Answer: asteroids
*Question*
Answer the following question given this paragraph: A chemical change occurs whenever matter changes into an entirely different substance with different chemical properties. Burning is an example of a chemical change. Q: What kind of change occurs whenever matter changes into an entirely different substance with different chemical properties? Choices: - reversible change - physical change - carbon change - chemical change A:
**Answer**
chemical change
*Question*
Answer the following question given this paragraph: Plants don't have immune systems, but they do respond to disease. Typically, their first line of defense is the death of cells surrounding infected tissue. This prevents the infection from spreading. Many plants also produce hormones and toxins to fight pathogens. For example, willow trees produce salicylic acid to kill bacteria. The same compound is used in many acne products for the same reason. Exciting new research suggests that plants may even produce chemicals that warn other plants of threats to their health, allowing the plants to prepare for their own defense. As these and other responses show, plants may be rooted in place, but they are far from helpless. Q: What do willow trees produce to kill bacteria? Choices: - chlorophyll - enzymes - cytoplasmic acid - salicylic acid A:
**Answer**
salicylic acid