Answer the following question given this paragraph: Organisms that reproduce sexually by joining gametes , a process known as fertilization , must have a mechanism to produce haploid gametes. This mechanism is meiosis , a type of cell division that halves the number of chromosomes. Meiosis occurs only in gamete producing cells within the gonads. During meiosis the pairs of chromosomes separate and segregate randomly to produce gametes with one chromosome from each pair. Meiosis involves two nuclear and cell divisions without an interphase in between, starting with one diploid cell and generating four haploid cells ( Figure below ). Each division, named meiosis I and meiosis II, has four stages: prophase, metaphase, anaphase, and telophase. These stages are similar to those of mitosis, but there are distinct and important differences. Q: What is the process in which organisms reproduce sexually by joining gametes called? Choices: - propagation - migration - stimulation - fertilization A:
fertilization
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Answer the following question given this paragraph: Genetic drift is a random change in allele frequencies that occurs in a small population. When a small number of parents produce just a few offspring, allele frequencies in the offspring may differ, by chance, from allele frequencies in the parents. Q: What is the term for a random change in allele frequencies that occurs in a small population? Choices: - evolution - speciation - mutation - genetic drift A:
genetic drift
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Answer the following question given this paragraph: 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. Q: What is another common term for single-unit smooth muscle? Choices: - abnormal muscle - lateral muscle - energies muscle - visceral muscle A:
visceral muscle
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Answer the following question given this paragraph: Angiosperms , or flowering seed plants, form seeds in ovaries. As the seeds develop, the ovaries may develop into fruits. Flowers attract pollinators, and fruits encourage animals to disperse the seeds. Q: What is the term for flowering seed plants? Choices: - spores - perennials - gymnosperms - angiosperms A:
angiosperms
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