Q: Q: What is another common term for single-unit smooth muscle? Read this paragraph and choose the correct option from the provided answers: Smooth muscle is organized in two ways: as single-unit smooth muscle, which is much more common; and as multiunit smooth muscle. The two types have different locations in the body and have different characteristics. Single-unit muscle has its muscle fibers joined by gap junctions so that the muscle contracts as a single unit. This type of smooth muscle is found in the walls of all visceral organs except the heart (which has cardiac muscle in its walls), and so it is commonly called visceral muscle. Because the muscle fibers are not constrained by the organization and stretchability limits of sarcomeres, visceral smooth muscle has a stress-relaxation response. This means that as the muscle of a hollow organ is stretched when it fills, the mechanical stress of the stretching will trigger contraction, but this is immediately followed by relaxation so that the organ does not empty its contents prematurely. This is important for hollow organs, such as the stomach or urinary bladder, which continuously expand as they fill. The smooth muscle around these organs also can maintain a muscle tone when the organ empties and shrinks, a feature that prevents "flabbiness" in the empty organ. In general, visceral smooth muscle produces slow, steady contractions that allow substances, such as food in the digestive tract, to move through the body. Multiunit smooth muscle cells rarely possess gap junctions, and thus are not electrically coupled. As a result, contraction does not spread from one cell to the next, but is instead confined to the cell that was originally stimulated. Stimuli for multiunit smooth muscles come from autonomic nerves or hormones but not from stretching. This type of tissue is found around large blood vessels, in the respiratory airways, and in the eyes. Choices: - abnormal muscle - lateral muscle - energies muscle - visceral muscle A:
A: visceral muscle

Q: Q: How many alleles control a characteristic? Read this paragraph and choose the correct option from the provided answers: A characteristic may be controlled by one gene with two alleles, but the two alleles may have a different relationship than the simple dominant-recessive relationship that you have read about so far. For example, the two alleles may have a codominant or incompletely dominant relationship. The former is illustrated by the flower in Figure below , and the latter in Figure below . Choices: - 3 - 4 - 8 - 2 A:
A: 2

Q: Q: In a cell cycle, what kind of regulator molecules allow advancement to the next stage? Read this paragraph and choose the correct option from the provided answers: 10.3 Control of the Cell Cycle Each step of the cell cycle is monitored by internal controls called checkpoints. There are three major checkpoints in the cell cycle: one near the end of G1, a second at the G2/M transition, and the third during metaphase. Positive regulator molecules allow the cell cycle to advance to the next stage. Negative regulator molecules monitor cellular conditions and can halt the cycle until specific requirements are met. Choices: - strong - similar - negative - positive A:
A: positive

Q: Q: What three rs represent the steps that you personally can take to conserve our natural resources and minimize waste? Read this paragraph and choose the correct option from the provided answers: Reduce, reuse, and recycle. There are steps that you personally can take to conserve our natural resources and reduce waste. The waste that an individual creates is small in proportion to all the waste produced by society. Yet all small contributions, when added up, make a difference. Choices: - rinse, reuse, recycle - remove, reduce, reuse - reduce, reuse, re-educate - reduce, reuse, recycle A:
A: reduce, reuse, recycle