Answer the following question given this paragraph: In polar covalent bonds, electrons are not shared equally between the two atoms, so one atom is slightly negative in charge and one is slightly positive in charge. In nonpolar covalent bonds, electrons are shared equally so the atoms remain neutral in charge. Q: Electrons are not shared equally between the two atoms in which type of covalent bonds? Choices: - wide - narrow - solar - polar A:
polar
(Question)
Answer the following question given this paragraph: Dilution of the products with water, followed by filtration to remove calcium sulfate, gives a dilute acid solution contaminated with calcium dihydrogen phosphate, Ca(H2PO4)2, and other compounds associated with calcium phosphate rock. It is possible to prepare pure orthophosphoric acid by dissolving P4O10 in water. The action of water on P4O6, PCl3, PBr3, or PI3 forms phosphorous acid, H3PO3 (shown in Figure 18.53). The best method for preparing pure phosphorous acid is by hydrolyzing phosphorus trichloride: PCl 3(l) + 3H 2 O(l) H 3 PO 3(aq) + 3HCl(g) Heating the resulting solution expels the hydrogen chloride and leads to the evaporation of water. When sufficient water evaporates, white crystals of phosphorous acid will appear upon cooling. The crystals are deliquescent, very soluble in water, and have an odor like that of garlic. The solid melts at 70.1 C and decomposes at about 200 C by disproportionation into phosphine and orthophosphoric acid: 4H 3 PO 3(l) PH 3(g) + 3H 3 PO 4(l). Q: The best method for preparing pure phosphorous acid is by hydrolyzing what? Choices: - dioxide trichloride - carbon trichloride - dioxide phosphat - phosphorus trichloride A:
(Answer)
phosphorus trichloride
Ques: Answer the following question given this paragraph: Protists are eukaryotes in the Protist Kingdom. Most are single-celled organisms. Protists are thought to be the oldest eukaryotes. They probably evolved when some prokaryotic cells invaded or were engulfed by others. Q: What is thought to be the oldest eukaryotes? Choices: - amoebas - prokaryotes - arthropods - protists A:
Ans: protists
(Q).
Answer the following question given this paragraph: The process that produces haploid gametes is meiosis. Meiosis is a type of cell division in which the number of chromosomes is reduced by half. It occurs only in certain special cells of the organisms. During meiosis, homologous chromosomes separate, and haploid cells form that have only one chromosome from each pair. Two cell divisions occur during meiosis, and a total of four haploid cells are produced. The two cell divisions are called meiosis I and meiosis II. The overall process of meiosis is summarized in Figure below . You can watch an animation of meiosis at this link: http://www. youtube. com/watch?v=D1_-mQS_FZ0 . Q: What is the type of cell division where the number of chromosomes is reduced in half? Choices: - cloning - mitosis - interphase - meiosis A:
(A).
meiosis
Ques:Answer the following question given this paragraph: Roundworms make up the phylum Nematoda. They have a pseudocoelom and hydrostatic skeleton. Their body is covered with tough cuticle. Free-living roundworms are found mainly in freshwater habitats. Parasitic roundworms have a variety of hosts, including humans. Q: What has a pseudocoelom and hydrostatic skeleton? Choices: - vertebrates - omnivores - gymnosperms - roundworms A:

Ans:roundworms
Answer the following question given this paragraph: Mollusks reproduce sexually. Most species have separate male and female sexes. Gametes are released into the mantle cavity. Fertilization may be internal or external, depending on the species. Fertilized eggs develop into larvae. There may be one or more larval stages. Each one is different from the adult stage. Mollusks (and annelids) have a unique larval form called a trochophore. It is a tiny organism with cilia for swimming. Q: The trochophre, a unique larval form, is found in the life cycle of which animal classification. Choices: - eels - coral - sharks - mollusks A:
mollusks