Q: Because of their reactivity, we do not find most representative metals as free elements where? Read this paragraph and choose the correct option from the provided answers: [PCl 3][Cl 2] (0.135)(0.135) = = 0.021 0.87 [PCl 5] The equilibrium constant calculated from the equilibrium concentrations is equal to the value of Kc given in the problem (when rounded to the proper number of significant figures). Thus, the calculated equilibrium concentrations check. Kc =. Choices: - in water - in the atomospher - underground - in nature A:
in nature

Q: What is a pure substance called? Read this paragraph and choose the correct option from the provided answers: A pure substance is called an element . An element is a pure substance because it cannot be separated into any other substances. Currently, 92 different elements are known to exist in nature, although additional elements have been formed in labs. All matter consists of one or more of these elements. Some elements are very common; others are relatively rare. The most common element in the universe is hydrogen, which is part of Earth's atmosphere and a component of water. The most common element in Earth's atmosphere is nitrogen, and the most common element in Earth's crust is oxygen. Several other elements are described in the musical video at this URL:. Choices: - a mixture - homogeneous matter - a liquid - an element A:
an element

Q: Q: Oxygenated air, taken in during inhalation, diffuses across the surface of the lungs into the what? Read this paragraph and choose the correct option from the provided answers: Types of Breathing Amphibians have evolved multiple ways of breathing. Young amphibians, like tadpoles, use gills to breathe, and they don't leave the water. Some amphibians retain gills for life. As the tadpole grows, the gills disappear and lungs grow. These lungs are primitive and not as evolved as mammalian lungs. Adult amphibians are lacking or have a reduced diaphragm, so breathing via lungs is forced. The other means of breathing for amphibians is diffusion across the skin. To aid this diffusion, amphibian skin must remain moist. Birds face a unique challenge with respect to breathing: They fly. Flying consumes a great amount of energy; therefore, birds require a lot of oxygen to aid their metabolic processes. Birds have evolved a respiratory system that supplies them with the oxygen needed to enable flying. Similar to mammals, birds have lungs, which are organs specialized for gas exchange. Oxygenated air, taken in during inhalation, diffuses across the surface of the lungs into the bloodstream, and carbon dioxide diffuses from the blood into the lungs and expelled during exhalation. The details of breathing between birds and mammals differ substantially. In addition to lungs, birds have air sacs inside their body. Air flows in one direction from the posterior air sacs to the lungs and out of the anterior air sacs. The flow of air is in the opposite direction from blood flow, and gas exchange takes place much more efficiently. This type of breathing enables birds to obtain the requisite oxygen, even at higher altitudes where the oxygen concentration is low. This directionality of airflow requires two cycles of air intake and exhalation to completely get the air out of the lungs. Choices: - liver - brain - proteins - bloodstream A:
A: bloodstream

Question: Q: Why are continents unable to be pushed down into the mantle by plate boundaries? Read this paragraph and choose the correct option from the provided answers: Most of the world's largest mountains form as plates collide at convergent plate boundaries. Continents are too buoyant to get pushed down into the mantle. So when the plates smash together, the crust crumples upwards. This creates mountains. Folding and faulting in these collision zones makes the crust thicker. Choices: - gravity - surface tension - density - buoyancy A:
Answer: buoyancy

*Question*
Q: How many directions can ions flow along the axon? Read this paragraph and choose the correct option from the provided answers: Choices: - two - six - three - one A:
**Answer**
one

*Question*
Q: What term is used to describe a cross between two individuals that have different traits? Read this paragraph and choose the correct option from the provided answers: Mendel first worked with plants that differed in a single characteristic, such as flower color. A hybridization is a cross between two individuals that have different traits. A hybridization in which only one characteristic is examined is called a monohybrid cross . The offspring of such a cross are called monohybrids. Mendel noted that hybridizing true-breeding (P generation) plants gave rise to an F 1 generation that showed only one trait of a characteristic. For example, a true-breeding purple-flowering plant crossed with a true-breeding white-flowering plant always gave rise to purple-flowered hybrid plants. There were no white-flowered hybrids. Mendel wanted to know what happened to the white-flowers. If indeed a "heritable factor" for white-flower had disappeared, all future offspring of the hybrids would be purple-flowered - none would be white. To test this idea, Mendel let the F 1 generation plants self-pollinate and then planted the resulting seeds. Choices: - assimilation - fraternization - purebreed - hybridization A:
**Answer**
hybridization