Q: Many ceramics are composed of what, which are salts containing anions composed of silicon and oxygen? Read this paragraph and choose the correct option from the provided answers: At 1600 C, quartz melts to yield a viscous liquid. When the liquid cools, it does not crystallize readily but usually supercools and forms a glass, also called silica. The SiO4 tetrahedra in glassy silica have a random arrangement characteristic of supercooled liquids, and the glass has some very useful properties. Silica is highly transparent to both visible and ultraviolet light. For this reason, it is important in the manufacture of lamps that give radiation rich in ultraviolet light and in certain optical instruments that operate with ultraviolet light. The coefficient of expansion of silica glass is very low; therefore, rapid temperature changes do not cause it to fracture. CorningWare and other ceramic cookware contain amorphous silica. Silicates are salts containing anions composed of silicon and oxygen. In nearly all silicates, sp3-hybridized silicon atoms occur at the centers of tetrahedra with oxygen at the corners. There is a variation in the silicon-to-oxygen ratio that occurs because silicon-oxygen tetrahedra may exist as discrete, independent units or may share oxygen atoms at corners in a variety of ways. In addition, the presence of a variety of cations gives rise to the large number of silicate minerals. Many ceramics are composed of silicates. By including small amounts of other compounds, it is possible to modify the physical properties of the silicate materials to produce ceramics with useful characteristics. Choices: - vinylates - crystals - soils - silicates A:
silicates

Q: Distinguishing between homology and analogy is critical in reconstructing what? Read this paragraph and choose the correct option from the provided answers: Choices: - residues - phylums - proteases - phylogenies A:
phylogenies

Q: Q: When is the sun directly over the equator? Read this paragraph and choose the correct option from the provided answers: Solstice refers to the position of the Sun when it is closest to one of the poles. At equinox, the Sun is directly over the Equator. Choices: - Winter - Midsummer - Fall - equinox A:
A: equinox

Question: Q: What two systems are the lungs part of? Read this paragraph and choose the correct option from the provided answers: The organs of the excretory system are also parts of other organ systems. For example, your lungs are part of the respiratory system. Your lungs remove carbon dioxide from your body, so they are also part of the excretory system. More organs of the excretory system are listed below ( Table below ). Choices: - stomach and excretory - heart and excretory - stomach and nervous - respiratory and excretory A:
Answer: respiratory and excretory

*Question*
Q: Each pollen grain has two coverings: the exine (thicker, outer layer) and the what? Read this paragraph and choose the correct option from the provided answers: Each pollen grain has two coverings: the exine (thicker, outer layer) and the intine (Figure 32.7). The exine contains sporopollenin, a complex waterproofing substance supplied by the tapetal cells. Sporopollenin allows the pollen to survive under unfavorable conditions and to be carried by wind, water, or biological agents without undergoing damage. Female Gametophyte (The Embryo Sac) While the details may vary between species, the overall development of the female gametophyte has two distinct phases. First, in the process of megasporogenesis, a single cell in the diploid megasporangiuman area of tissue in the ovulesundergoes meiosis to produce four megaspores, only one of which survives. During the second phase, megagametogenesis, the surviving haploid megaspore undergoes mitosis to produce an eight-nucleate, seven-cell female gametophyte, also known as the megagametophyte or embryo sac. Two of the nucleithe polar nucleimove to the equator and fuse, forming a single, diploid central cell. This central cell later fuses with a sperm to form the triploid endosperm. Three nuclei position themselves on the end of the embryo sac opposite the micropyle and develop into the antipodal cells, which later degenerate. The nucleus closest to the micropyle becomes the female gamete, or egg cell, and the two adjacent nuclei develop into synergid cells (Figure 32.8). The synergids help guide the pollen tube for successful fertilization, after which they disintegrate. Once fertilization is complete, the resulting diploid zygote develops into the embryo, and the fertilized ovule forms the other tissues of the seed. Choices: - tube nucleus - pollen tube - cytoplasm - intine A:
**Answer**
intine

(Question)
Q: What is moving air called? Read this paragraph and choose the correct option from the provided answers: Moving air, like moving water, causes erosion. Moving air is called wind. Choices: - steam - clouds - humidity - wind A:
(Answer)
wind