NEX Exam Dumps - Nursing Entrance Exam (Math, Science and Verbal)

An ionic bond forms when one atom completely transfers one or more electrons to another atom. This typically occurs between a metal and a nonmetal, resulting in the formation of positively and negatively charged ions that attract each other. In contrast, covalent bonds involve sharing of electrons. Non-polar covalent bonds share electrons equally, while polar covalent bonds share electrons unequally. Hydrogen bonds are weak attractions between molecules, not true electron-sharing or transfer bonds. The NEX Science exam frequently assesses basic chemistry principles related to bonding and molecular interactions. Because only ionic bonds involve a complete transfer of electrons, option D is correct.

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This question tests measurement interpretation using an ocular micrometer, a skill often assessed on the NEX Science exam. An ocular micrometer is a scale placed in the eyepiece of a microscope and must be interpreted based on the given scale value. In this problem, each division equals 25 micrometers. By carefully counting the number of divisions spanned by the oval in the image, the oval covers8 divisions. To find the total length, the number of divisions is multiplied by the micrometer value per division: 8 × 25 micrometers = 200 micrometers. The other answer choices represent common calculation errors, such as counting too few or too many divisions or using an incorrect multiplication factor. The key to these questions is slow, accurate counting and correct unit conversion. The NEX exam frequently includes microscopy-based questions to assess practical lab interpretation skills.

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Negative feedback occurs when a change in a physiological variable triggers a response that counteracts the initial change, helping maintain homeostasis. When blood glucose levels rise, the pancreas releases insulin, which promotes glucose uptake by cells and lowers blood glucose back to normal levels. This is a classic example of negative feedback. Option B is incorrect because thyroxine increases metabolism, not decreases it. Options A and D do not clearly demonstrate a direct feedback loop restoring balance. The NEX Science exam often highlights glucose regulation as a key example of negative feedback because it clearly illustrates cause-and-effect relationships within endocrine control systems.

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This question tests understanding of predator–prey relationships, a key ecology concept on the NEX Science exam. Wolves are the natural predators of moose on Isle Royale. When the moose population was initially high, there was an abundant food supply for wolves. This allowed the wolf population to increase significantly. As the number of wolves increased, predation pressure on the moose population also increased, leading to a sharp decline in moose numbers. This inverse relationship between predator and prey populations is a classic ecological pattern. There is no evidence in the question to suggest disease, human hunting, or breeding rate differences as the primary cause. Instead, the changes in population sizes are best explained by increased predation. The NEX often assesses whether students can interpret real-world ecological data and recognize how population dynamics are influenced by natural predator–prey interactions.

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A pathogen is any microorganism that causes disease in a host. Pathogens include bacteria, viruses, fungi, and parasites. Enzymes are proteins that speed up chemical reactions and are not microorganisms. Immune factors are components of the immune system that protect against disease. A vector is an organism, such as a mosquito or tick, that transmits pathogens but does not itself cause disease. The NEX Science exam commonly assesses understanding of infectious disease terminology and distinctions between disease-causing organisms and disease carriers. Recognizing pathogens as the direct cause of illness is a key concept in microbiology and public health.

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