imagine you have an element with atomic number 20 and mass number 40 how many neutrons does it have

ATI TEAS 7

TEAS Test 7 science

1. Imagine you have an element with atomic number 20 and mass number 40. How many neutrons does it have?

A. 20
B. 40
C. 10
D. 20

Correct answer: C

Rationale: - The atomic number (Z) represents the number of protons in an atom. In this case, the atomic number is 20. - The mass number (A) represents the total number of protons and neutrons in an atom. In this case, the mass number is 40. - To find the number of neutrons, you subtract the atomic number from the mass number: Neutrons = Mass number - Atomic number. - Neutrons = 40 - 20 = 20. - Therefore, the element with atomic number 20 and mass number 40 has 20 neutrons.

2. The Hardy-Weinberg equilibrium describes a population that is:

A. Undergoing rapid evolution due to strong directional selection.
B. Not evolving and at genetic equilibrium with stable allele frequencies.
C. Experiencing a founder effect leading to a reduction in genetic diversity.
D. Dominated by a single homozygous genotype that eliminates all variation.

Correct answer: B

Rationale: The Hardy-Weinberg equilibrium describes a theoretical population in which allele frequencies remain constant from generation to generation, indicating that the population is not evolving. This equilibrium occurs under specific conditions: no mutation, no gene flow, random mating, a large population size, and no natural selection. In this scenario, all genotypes are in proportion to the allele frequencies, and genetic diversity is maintained. Options A, C, and D do not accurately describe a population in Hardy-Weinberg equilibrium. Option A suggests rapid evolution due to strong directional selection, which would disrupt the equilibrium. Option C mentions a founder effect, which can reduce genetic diversity but is not a characteristic of a population in Hardy-Weinberg equilibrium. Option D describes a population dominated by a single homozygous genotype, which also does not align with the genetic diversity seen in a population at Hardy-Weinberg equilibrium.

3. Which of the following is a characteristic of a solution with high viscosity?

A. It flows easily
B. It has a low resistance to flow
C. It has a high resistance to flow
D. It does not mix with other liquids

Correct answer: C

Rationale: The correct answer is C: 'It has a high resistance to flow.' A solution with high viscosity exhibits a high resistance to flow. Viscosity measures the fluid's resistance to deformation or flow, with higher viscosity indicating thicker and slower-flowing fluids. Choice A is incorrect because high viscosity means the solution flows slowly, not easily. Choice B is incorrect as high viscosity implies a high resistance to flow, not a low one. Choice D is irrelevant to viscosity and does not describe a characteristic associated with high viscosity.

4. Chyle, a milky white fluid, is transported by lymphatic vessels from the:

A. Lungs
B. Intestines
C. Kidneys
D. Skin

Correct answer: B

Rationale: Chyle, a milky white fluid, is formed in the small intestine during digestion. It is composed of lymph and emulsified fats. Lymphatic vessels in the intestines, specifically lacteals, transport chyle from the intestines to the bloodstream for the distribution of nutrients throughout the body. The transport of chyle from the lungs, kidneys, or skin is not correct as these organs are not primarily involved in the production or transportation of chyle.