Answer the following question given this paragraph: Curiosity, the rover, has found evidence of a flowing stream on Mars. Layers of smooth, water-polished pebbles have been photographed. This is exactly what you would see in a stream on Earth. There are many surface features that look like water-eroded canyons. Since there was liquid water on Mars, scientists think that life might have existed there in the past. One of Curiosity's tasks is to sample the soil to search for carbon and other evidence of life. Q: Evidence for the presence of what on mars makes scientists think that life might have existed there in the past? Choices: - gas - plasma - air - water A:
water
(Question)
Answer the following question given this paragraph: When Earth first formed, it was a fiery hot, barren ball. It had no oceans or atmosphere. Rivers of melted rock flowed over its surface. Gradually, the planet cooled and formed a solid crust. Gases from volcanoes formed an atmosphere, although it contained only a trace of oxygen. As the planet continued to cool, clouds formed and rain fell. Rainwater helped form oceans. The ancient atmosphere and oceans would be toxic to modern life, but they set the stage for life to begin. Q: What did volcanic gases help to form on earth? Choices: - water - plants - rocks - atmosphere A:
(Answer)
atmosphere
Ques: Answer the following question given this paragraph: Immunodeficiency occurs when the immune system is not working properly. As a result, it cannot fight off pathogens that a normal immune system would be able to resist. Most commonly, immunodeficiency diseases occur when T or B cells (or both) do not work as well as they should, or when your body doesn't produce enough antibodies. Q: What happens when when the immune system does not work properly? Choices: - anemia - diabetes - stroke - immunodeficiency A:
Ans: immunodeficiency
(Q).
Answer the following question given this paragraph: You already know that a sour taste is one property of acids. ( Warning : Never taste an unknown substance to see whether it is an acid!) Acids have certain other properties as well. For example, acids can conduct electricity when dissolved in water because they consist of charged particles in solution. (Electric current is a flow of charged particles. ) Acids can also react with metals, and when they do they produce hydrogen gas. An example of this type of reaction is hydrochloric acid reacting with the metal zinc (Zn). The reaction is pictured in the Figure below . It can be represented by the chemical equation:. Q: Acids can also react with metals, and when they do they produce what? Choices: - alloys - potassium gas - rust - hydrogen gas A:
(A).
hydrogen gas
Ques:Answer the following question given this paragraph: Q: What are modified leaves that bear sporangia? Choices: - spines - neutrophils - sporozoans - sporophylls A:

Ans:sporophylls
Ques:Answer the following question given this paragraph: Echinoderms are named for their "spiny skin. " However, the spines aren't on their skin. They are part of the endoskeleton. The endoskeleton consists of calcium carbonate plates and spines, covered by a thin layer of skin. Adult echinoderms have radial symmetry . This is easy to see in the sea star and sand dollar in Figure above . However, echinoderms evolved from an ancestor with bilateral symmetry. Evidence for this is the bilateral symmetry of their larvae. Q: What are named for their "spiny skin"? Choices: - arachnids - reptiles - amphibians - echinoderms A:

Ans:
echinoderms