Q: An organism's unique role in the ecosystem is called its what? Read this paragraph and choose the correct option from the provided answers: Are you on the basketball team? Are you a cheerleader? Do you play an instrument in the band? Your niche would be your role or place in the school. Organisms also each have their own niche in the ecosystem. Is an organism a producer or a consumer? How does the organism interact with other organisms? Is the organism involved in any symbiotic relationships?. Choices: - focus - adaptation - purpose - niche A:
niche
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Q: When resources become limiting, populations follow a logistic growth curve in which the size will level off at a point called what? Read this paragraph and choose the correct option from the provided answers: 19.2 Population Growth and Regulation Populations with unlimited resources grow exponentiallywith an accelerating growth rate. When resources become limiting, populations follow a logistic growth curve in which population size will level off at the carrying capacity. Populations are regulated by a variety of density-dependent and density-independent factors. Life-history characteristics, such as age at first reproduction or numbers of offspring, are characteristics that evolve in populations just as anatomy or behavior can evolve over time. The model of r- and K-selection suggests that characters, and possibly suites of characters, may evolve adaptations to population stability near the carrying capacity (K-selection) or rapid population growth and collapse (r-selection). Species will exhibit adaptations somewhere on a continuum between these two extremes. Choices: - believed capacity - full capacity - containing capacity - carrying capacity A:
carrying capacity
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Q: What is the low level of radiation that occurs naturally in the environment called? Read this paragraph and choose the correct option from the provided answers: A low level of radiation occurs naturally in the environment. This is called background radiation. It comes from various sources. One source is rocks, which may contain small amounts of radioactive elements such as uranium. Another source is cosmic rays. These are charged particles that arrive on Earth from outer space. Background radiation is generally considered to be safe for living things. Choices: - temperature radiation - neon radiation - consequence radiation - background radiation A:
background radiation
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Q: An isometric type of what occurs as the muscle produces tension without changing the angle of a skeletal joint? Read this paragraph and choose the correct option from the provided answers: 10.4 | Nervous System Control of Muscle Tension By the end of this section, you will be able to: Explain concentric, isotonic, and eccentric contractions Describe the length-tension relationship Describe the three phases of a muscle twitch Define wave summation, tetanus, and treppe To move an object, referred to as load, the sarcomeres in the muscle fibers of the skeletal muscle must shorten. The force generated by the contraction of the muscle (or shortening of the sarcomeres) is called muscle tension. However, muscle tension also is generated when the muscle is contracting against a load that does not move, resulting in two main types of skeletal muscle contractions: isotonic contractions and isometric contractions. In isotonic contractions, where the tension in the muscle stays constant, a load is moved as the length of the muscle changes (shortens). There are two types of isotonic contractions: concentric and eccentric. A concentric contraction involves the muscle shortening to move a load. An example of this is the biceps brachii muscle contracting when a hand weight is brought upward with increasing muscle tension. As the biceps brachii contract, the angle of the elbow joint decreases as the forearm is brought toward the body. Here, the biceps brachii contracts as sarcomeres in its muscle fibers are shortening and cross-bridges form; the myosin heads pull the actin. An eccentric contraction occurs as the muscle tension diminishes and the muscle lengthens. In this case, the hand weight is lowered in a slow and controlled manner as the amount of crossbridges being activated by nervous system stimulation decreases. In this case, as tension is released from the biceps brachii, the angle of the elbow joint increases. Eccentric contractions are also used for movement and balance of the body. An isometric contraction occurs as the muscle produces tension without changing the angle of a skeletal joint. Isometric contractions involve sarcomere shortening and increasing muscle tension, but do not move a... Choices: - compression - extension - acceleration - contraction A:
contraction
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