Free Scientific Reasoning MCQs with Answers

81. In human blood, calcium (Ca2+) concentration is regulated by vitamin D3. First vitamin D3 is converted to calcidiol (CD) in the liver. An elevated concentration of CD inhibits furhter conversion of vitamin D3. Next, CD is conceverted to calcitriol (CT) in the kidneys in a reaction tht requires parathyroid hormone (PTH). An elevated concentration of CT increases Ca2+ concentration, which in turn inhibits further release of PTH. See figure 1According to Figure 3, the relative blood CT concentration is between 5 times normal and 6 times normal within which of the following blood Ca2+ concentration ranges?

• A. 8mg/100 mL to 9mg/100 mL
• B. 10mg/100 mL to 11mg/100 mL
• C. 11mg/100 mL to 12mg/100 mL
• D. 13mg/100 mL to 14mg/100 mL

Explanation: Looking at figure 3, it is clear that only at blood Ca2+ concentration range of 8mg/100 mL to 9mg/100 mL, the relative blood CT concentration is between 5 times normal and 6 times normal.

82. Procaine is a medication used for analgesia before a procedural intervention. It is a pharmaceutical medication belonging to the aminoester group of local anesthetics and it is commonly found as Nitrobenzoic acids, a derivative of benzoic acid. German chemist Alfred Einhorn first synthesized the drug as a safer anesthetic alternative to cocaine due to its side effect profile, patenting procaine under the trade name "Novocain". Historically, procaine has been used for local, regional, and neuraxial anesthesia via local infiltration, peripheral nerve blockade, and intrathecal injection. Nitrobenzoic acid can also have other isomers which have completely different uses and cannot be used as an alternative to Novacin. How many position isomers can Nitrobenzoic acid possibly form?

• A. 4
• B. 3
• C. 5
• D. 6

Explanation: Nitrobenzoic acid, with the molecular formula C7H5NO4, can have different position isomers based on the arrangement of the nitro group (NO2) on the benzene ring

83. A solute is any substance that is dissolved in another substance, which is called the solvent. A student tested the solubility (a measure of how much solute will dissolve into the solvent) of six different substances. The solubility of a substance at a given temperature is defined as the concentration of the dissolved solute that is in equilibrium with the solvent. Table 1 represents the concentration of dissolved substances in 100 grams of water at various temperatures. The concentrations are expressed in grams of solute per 100 grams of water.The data shown in table 1 support the conclusion that, for a given substance as the temperature of the water increases, the amount of solute that can be dissolved

• A. Increases only
• B. Decreases only
• C. Varies but with a trend depending on substance
• D. Varies but with no trend

Explanation: The best answer is C. It is clear from the table that each substance reacts differently in its solubility depending on the temperature. However, each substance does show a clear trend in whether it gets more or less soluble with increasing temperature.

84. The atmosphere is made up of 4 distinct layers: the troposphere, stratosphere, mesosphere, and thermosphere. Different types of clouds form in the different layers depending on the pressure in the atmosphere and the ambient temperature. The cloud types include nimbus, stratus, cumulus, and cirrus. Figure 1 shows the location of the barriers of the atmosphere when the temperature and pressure are at an ideal condition for cloud formation. It also shows the different types of clouds formed at the different levels. Note: Clouds are formed mostly of water crystals, but can also contain particles of rock and dust.According to figure 1, the atmospheric layer with the greatest range in pressure is the

• A. Mesosphere
• B. Thermosphere
• C. Stratosphere
• D. Troposphere

Explanation: By looking at Figure 1, you can determine the range in pressure at which each atmospheric layer can exist. Beginning with answer choice a, calculate the difference between the lowest pressure and the highest pressure at which the atmospheric layer can exist: Mesosphere: 14.5 psi − 7.5 psi = 7 psi Thermosphere: 17.8 psi − 10.3 psi = 7.5 psi Stratosphere: 9.5 psi − 3.8 psi = 5.7 psi Troposphere: 5.0 psi − 1.0 psi = 4.0 psi The pressure in the thermosphere has the greatest range, answer choice B.

85. The atmosphere is made up of 4 distinct layers: the troposphere, stratosphere, mesosphere, and thermosphere. Different types of clouds form in the different layers depending on the pressure in the atmosphere and the ambient temperature. The cloud types include nimbus, stratus, cumulus, and cirrus. Figure 1 shows the location of the barriers of the atmosphere when the temperature and pressure are at an ideal condition for cloud formation. It also shows the different types of clouds formed at the different levels. Note: Clouds are formed mostly of water crystals, but can also contain particles of rock and dust.Which of the following statements about the formation of cumulus clouds is supported by data presented in figure 1Cumulus clouds form typically in

• A. Pressures between 8 and 12 psi and at an average temperature of 35 degree c
• B. Pressures between 12 and 16 psi and at an average temperature of 22 degree c
• C. Pressure of 4 psi and at average temperatures between 12 and 22 degree c
• D. Pressure of 18 psi and at average temperatures between 50 and 60 degree c

Explanation: To answer this question you need to look at the information on cumulus clouds in Figure 1. Figure 1 suggests that cumulus clouds form in the mesosphere. The mesosphere's pressure ranges from 8 psi to 12 psi, and the average temperature for this range is 35◦ C. This information supports answer choice A.

86. The atmosphere is made up of 4 distinct layers: the troposphere, stratosphere, mesosphere, and thermosphere. Different types of clouds form in the different layers depending on the pressure in the atmosphere and the ambient temperature. The cloud types include nimbus, stratus, cumulus, and cirrus. Figure 1 shows the location of the barriers of the atmosphere when the temperature and pressure are at an ideal condition for cloud formation. It also shows the different types of clouds formed at the different levels. Note: Clouds are formed mostly of water crystals, but can also contain particles of rock and dust.According to fig 1 as pressure within the atmosphere layers increases, temperature within the atmospheric layers

• A. Increases only
• B. Decreases only
• C. Increases up to 6 psi, then decreases
• D. Decreases up to 10 psi then increases

Explanation: The key in Figure 1 includes two lines: temperature and pressure. As the pressure line is increasing (positive slope), the temperature line is decreasing (negative slope). This suggests that as pressure within the atmospheric layer increases, temperature decreases only, answer choice B.

87. The atmosphere is made up of 4 distinct layers: the troposphere, stratosphere, mesosphere, and thermosphere. Different types of clouds form in the different layers depending on the pressure in the atmosphere and the ambient temperature. The cloud types include nimbus, stratus, cumulus, and cirrus. Figure 1 shows the location of the barriers of the atmosphere when the temperature and pressure are at an ideal condition for cloud formation. It also shows the different types of clouds formed at the different levels. Note: Clouds are formed mostly of water crystals, but can also contain particles of rock and dust.According to the information given in figure 1, clouds within the stratosphere are most likely formed

• A. Under a pressure of 4 psi and 20 degree C
• B. Under a pressure of 10 psi and 30 degree C
• C. Over a pressure of 12 psi and 40 degree C
• D. Over a pressure of 14 psi and 50 degree C

Explanation: Answering this question requires you to look carefully at the range of temperature and pressure combinations at which clouds in the stratosphere form, as shown in Figure 1. Because the clouds here begin to form under 30◦ C and most are located below a pressure of 10 psi, this combination is correct. The other choices designate ranges of the atmosphere either above or below the stratosphere.

88. The atmosphere is made up of 4 distinct layers: the troposphere, stratosphere, mesosphere, and thermosphere. Different types of clouds form in the different layers depending on the pressure in the atmosphere and the ambient temperature. The cloud types include nimbus, stratus, cumulus, and cirrus. Figure 1 shows the location of the barriers of the atmosphere when the temperature and pressure are at an ideal condition for cloud formation. It also shows the different types of clouds formed at the different levels. (Note: Clouds are formed mostly of water crystals, but can also contain particles of rock and dust.)If a pressure of 7 psi were sustained within the atmosphere, according to the image, which of the following types of clouds would likely form?

• A. Cirrus
• B. Cumulus
• C. Nimbus
• D. Stratus

Explanation: At a pressure of 7 psi, the image shows that cloud formation will most likely occur in the stratosphere. According to that, clouds that form in the stratosphere are stratus clouds. This information best supports answer choice D.

89. What is the correct order of the capacitances of these circuits, from lowest to highest? Assume all capacitances have the same capacitance.

• A. B<A<C<D
• B. D<C<B<A
• C. C<B<A<D
• D. D<C<A<B

Explanation: Assuming the capacitance is one, then calculations can be made. A has ⅔ C or 0.66 C as its capacitance, B has 6/10 C or 0.6 C , C has ½ C or 0.5 C, D has 3/2 or 1.5 C as its capacitance.

90. Dinitrophenol is a metabolic poison that prevents the production of ATP. What will happen when a resting axon is treated with such a poison?

• A. The charge inside the axon membrane becomes more negative
• B. The charge outside the axon membrane becomes less positive
• C. The charge inside the axon membrane becomes less positive
• D. The charge outside the axon membrane does not change

Explanation: So, when an axon is at rest, the anions give it a negative charge, the sodium pumps keep sodium out and potassium in, and the sodium gates and potassium gates are all closed. Because of the positive-negative difference between the inside and outside, this resting state is called a resting potential.The ion channels carry electrical charges necessary to keep the channels open, especially K + ^+ + channels, to establish the membrane potential. ATP is the energy that maintains the channels found throughout the cell membrane. If no ATP can be produced the following happens, the charge outside the axon membrane becomes less positive, hence the option is correct.