Answer the following question given this paragraph: The mechanical advantage of a machine is the factor by which the machine changes the input force. It equals the ratio of the output force to the input force. A wheel and axle may either increase or decrease the input force, depending on whether the input force is applied to the axle or the wheel. Q: What is indicated by the ratio of the output force to the input force in a machine? Choices: - momentum - magnetic force - man hours - mechanical advantage A:
mechanical advantage
(Question)
Answer the following question given this paragraph: Most of the atmosphere is nitrogen, but it doesn't do much. Carbon dioxide and oxygen are the gases in the atmosphere that are needed for life. Q: What is the most prevalent gas in the atmosphere, but not the most vital for life? Choices: - carbon dioxide - oxygen - argon - nitrogen A:
(Answer)
nitrogen
Ques: Answer the following question given this paragraph: The Mucosal Immune Response Mucosal tissues are major barriers to the entry of pathogens into the body. The IgA (and sometimes IgM) antibodies in mucus and other secretions can bind to the pathogen, and in the cases of many viruses and bacteria, neutralize them. Neutralization is the process of coating a pathogen with antibodies, making it physically impossible for the pathogen to bind to receptors. Neutralization, which occurs in the blood, lymph, and other body fluids and secretions, protects the body constantly. Neutralizing antibodies are the basis for the disease protection offered by vaccines. Vaccinations for diseases that commonly enter the body via mucous membranes, such as influenza, are usually formulated to enhance IgA production. Immune responses in some mucosal tissues such as the Peyer's patches (see Figure 21.11) in the small intestine take up particulate antigens by specialized cells known as microfold or M cells (Figure 21.27). These cells allow the body to sample potential pathogens from the intestinal lumen. Dendritic cells then take the antigen to the regional lymph nodes, where an immune response is mounted. Q: What type of tissues are major barriers to the entry of pathogens into the body? Choices: - skin - vascular - nasal - mucosal A:
Ans: mucosal
(Q).
Answer the following question given this paragraph: Carbon-14 has a relatively short half-life. It decays quickly compared to some other unstable isotopes. So carbon-14 dating is useful for specimens younger than 50,000 years old. That's a blink of an eye in geologic time. But radiocarbon dating is very useful for more recent events. One important use of radiocarbon is early human sites. Carbon-14 dating is also limited to the remains of once-living things. To date rocks, scientists use other radioactive isotopes. Q: What property of carbon and other elements can be used to date fossils and rocks, among other things? Choices: - mass - full-life - magnetic force - half-life A:
(A).
half-life
Ques:Answer the following question given this paragraph: Phosphate groups are found within phospholipids and nucleotides. Q: Phosphate groups are found within phospholipids and what else? Choices: - amino acids - carotenoids - hydrocarbon chains - nucleotides A:

Ans:nucleotides
Ques:Answer the following question given this paragraph: Gap genes themselves are under the effect of maternal effect genes, such as bicoid and nanos. Gap genes also regulate each other to achieve their precise striped expression patterns. The maternal effect is when the phenotype of offspring is partly determined by the phenotype of its mother, irrespective of genotype. This often occurs when the mother supplies mRNA or proteins to the egg, affecting early development. In developing Drosophila, maternal effects include axis determination. Q: What is the term for when the phenotype of offspring is partly determined by the phenotype of its mother, irrespective of genotype? Choices: - congenital effect - uterine effect - oceanic effect - maternal effect A:

Ans:
maternal effect