Answer the following question given this paragraph: Before the atmosphere became oxygenated, the planet was subjected to strong radiation; thus, the first organisms would have flourished where they were more protected, such as in ocean depths or beneath the surface of Earth. At this time, too, strong volcanic activity was common on Earth, so it is likely that these first organismsthe first prokaryoteswere adapted to very high temperatures. These are not the typical temperate environments in which most life flourishes today; thus, we can conclude that the first organisms that appeared on Earth likely were able to withstand harsh conditions. Microbial mats may represent the earliest forms of life on Earth, and there is fossil evidence of their presence, starting about 3.5 billion years ago. A microbial mat is a large biofilm, a multi-layered sheet of prokaryotes (Figure 13.3a), including mostly bacteria, but also archaea. Microbial mats are a few centimeters thick, and they typically grow on moist surfaces. Their various types of prokaryotes carry out different metabolic pathways, and for this reason, they reflect various colors. Prokaryotes in a microbial mat are held together by a gummy-like substance that they secrete. The first microbial mats likely obtained their energy from hydrothermal vents. A hydrothermal vent is a fissure in Earth's surface that releases geothermally heated water. With the evolution of photosynthesis about 3 billion years ago, some prokaryotes in microbial mats came to use a more widely available energy sourcesunlightwhereas others were still dependent on chemicals from hydrothermal vents for food. Q: Before the atmosphere became oxygenated, the planet was subjected to what harmful energy source, meaning the first organisms would have flourished where they were more protected? Choices: - evaporation - conduction - convection - radiation A:
radiation
Answer the following question given this paragraph: Basic Principles of Gas Exchange Gas exchange during respiration occurs primarily through diffusion. Diffusion is a process in which transport is driven by a concentration gradient. Gas molecules move from a region of high concentration to a region of low concentration. Blood that is low in oxygen concentration and high in carbon dioxide concentration undergoes gas exchange with air in the lungs. The air in the lungs has a higher concentration of oxygen than that of oxygen-depleted blood and a lower concentration of carbon dioxide. This concentration gradient allows for gas exchange during respiration. Partial pressure is a measure of the concentration of the individual components in a mixture of gases. The total pressure exerted by the mixture is the sum of the partial pressures of the components in the mixture. The rate of diffusion of a gas is proportional to its partial pressure within the total gas mixture. This concept is discussed further in detail below. Q: Gas exchange during respiration occurs primarily through what? Choices: - vaporization - secretion - activation - diffusion A:
diffusion
Q: Answer the following question given this paragraph: The strength of a base depends on how many hydroxide ions it produces when it dissolves in water. A stronger base produces more hydroxide ions than a weaker base. For example, sodium hydroxide (NaOH), a base in drain cleaner, is a strong base because all of it breaks down into ions when it dissolves in water. Calcium carbonate (CaCO 3 ), a base in antacids, is a weak base because only a small percentage of it breaks down into ions in water. Q: What determines the strength of a base when dissolved in water? Choices: - amount of phosphorus ions produced - pH level - saline content - amount of hydroxide ions produced A:
A: amount of hydroxide ions produced
Question: Answer the following question given this paragraph: The Role of Energy in Chemical Reactions Chemical reactions require a sufficient amount of energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ones formed. In general, kinetic energy is the form of energy powering any type of matter in motion. Imagine you are building a brick wall. The energy it takes to lift and place one brick atop another is kinetic energythe energy matter possesses because of its motion. Once the wall is in place, it stores potential energy. Potential energy is the energy of position, or the energy matter possesses because of the positioning or structure of its components. If the brick wall collapses, the stored potential energy is released as kinetic energy as the bricks fall. In the human body, potential energy is stored in the bonds between atoms and molecules. Chemical energy is the form of potential energy in which energy is stored in chemical bonds. When those bonds are formed, chemical energy is invested, and when they break, chemical energy is released. Notice that chemical energy, like all energy, is neither created nor destroyed; rather, it is converted from one form to another. When you eat an energy bar before heading out the door for a hike, the honey, nuts, and other foods the bar contains are broken down and rearranged by your body into molecules that your muscle cells convert to kinetic energy. Chemical reactions that release more energy than they absorb are characterized as exergonic. The catabolism of the foods in your energy bar is an example. Some of the chemical energy stored in the bar is absorbed into molecules your body uses. Q: In general, kinetic energy is the form of energy powering any type of matter in motion, while the energy of position is called what? Choices: - mechanical energy - magnetic energy - thermal energy - potential energy A:
Answer: potential energy
*Question*
Answer the following question given this paragraph: In some places, the oceanic crust comes up to a continent. The moving crust pushes that continent away from the ridge axis as well. If the moving oceanic crust reaches a deep sea trench, the crust sinks into the mantle. The creation and destruction of oceanic crust is the reason that continents move. Seafloor spreading is the mechanism that Wegener was looking for!. Q: What happens to the crust if the moving oceanic crust reaches a deep sea trench? Choices: - ocean volcano - it cleaves - forms a continent - sinks into mantle A:
**Answer**
sinks into mantle
Q: Answer the following question given this paragraph: Fungus-like protists are molds. They are absorptive feeders, found on decaying organic matter. They resemble fungi and reproduce with spores as fungi do. Examples of fungus-like protists include slime molds and water molds. Q: How do fungus-like protists such as slime molds reproduce? Choices: - photosynthesis - sexually - asexually - with spores A:
A: with spores