Nokea
What is the initial step of the scientific method?
- A. construct a hypothesis
- B. make observations
- C. analyze data
- D. form a question
Correct Answer: B
Rationale: The first step of the scientific method is to make observations. This involves collecting data and information about a specific phenomenon or problem. Observations serve as the basis for developing a question to be explored further. Forming a hypothesis (Choice A) comes after making observations, as the hypothesis is an educated guess to explain the observations. Analyzing data (Choice C) occurs later in the scientific method after data has been collected and experiments conducted. Forming a question (Choice D) is a crucial step but typically follows observations in the scientific process.
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Which of the following is a type of white blood cell that plays a key role in adaptive immunity by seeking out, attacking, and destroying targeted pathogens?
- A. memory B cells
- B. neutrophils
- C. antibodies
- D. cytotoxic T cells
Correct Answer: D
Rationale: The correct answer is cytotoxic T cells. Cytotoxic T cells are a type of white blood cell that is crucial in adaptive immunity. They are specialized in recognizing and destroying infected or abnormal cells in the body. Neutrophils are primarily involved in innate immunity, providing rapid response to infections. Antibodies are proteins produced by B cells and are essential in specific immune responses, but they do not directly attack pathogens. Memory B cells are part of the adaptive immune response, responsible for mounting a quicker and stronger response upon re-exposure to a pathogen. However, they do not directly seek out and destroy pathogens like cytotoxic T cells do.
Where does fertilization typically occur in the female reproductive system?
- A. uterus
- B. fallopian tube
- C. endometrium
- D. ovary
Correct Answer: B
Rationale: Fertilization typically occurs in the fallopian tube, specifically in the ampulla, which is the widest part of the tube. After ovulation, the released egg travels through the fallopian tube where it may encounter sperm for fertilization to take place. The fallopian tube provides the ideal environment for fertilization due to the presence of cilia that help move the egg and sperm towards each other. The uterus is where the fertilized egg will implant and develop into a fetus, not where fertilization occurs. The endometrium is the lining of the uterus that thickens to support a potential pregnancy but is not the site of fertilization. The ovary releases the egg during ovulation but is not where fertilization occurs.
Which of the following is a true statement about dominance in genetics?
- A. All genes adhere to Mendel's law of dominance.
- B. A dominant allele will always be expressed.
- C. When two dominant alleles are present, the resulting phenotype will express both traits.
- D. There are three or more alleles possible for all genes.
Correct Answer: B
Rationale: In genetics, dominance refers to the relationship between two different alleles of a gene where one allele (dominant) masks the expression of another allele (recessive) in an individual's phenotype. The correct statement about dominance is that a dominant allele will always be expressed in the phenotype, even in the presence of a recessive allele. This means that if an individual has at least one dominant allele for a particular trait, that trait will be expressed. Choice A is incorrect because not all genes follow Mendel's law of dominance; exceptions do exist. Choice C is incorrect because when two dominant alleles are present, only one will be expressed due to complete dominance. Choice D is incorrect as there can be more than three alleles for a gene, and not all genes have three or more alleles.
What describes a cell's reaction to being placed in a hypertonic solution?
- A. The cell will shrink as water is pulled out of the cell to equalize the concentrations inside and outside of the cell.
- B. The cell will swell as water is pulled into the cell to equalize the concentrations inside and outside of the cell.
- C. The cell will remain the same size since the concentrations inside and outside the cell are equal to begin with.
- D. The pH inside the cell will drop in order to equalize the pH inside and outside the cell.
Correct Answer: A
Rationale: A cell placed in a hypertonic solution has a higher solute concentration outside the cell compared to inside. This creates a concentration gradient that causes water to move out of the cell through osmosis to equalize the concentrations on both sides. As a result, the cell will shrink or undergo plasmolysis, as water is pulled out of the cell. Choice B is incorrect because a hypertonic solution causes water to move out of the cell, leading to shrinkage rather than swelling. Choice C is incorrect as a hypertonic solution results in a concentration gradient that leads to water leaving the cell, causing it to shrink. Choice D is incorrect because pH is not directly affected by being placed in a hypertonic solution; the change in solute concentration primarily impacts water movement.
Which of the following describes the path through which air moves during inhalation?
- A. mouth/nose > pharynx > larynx > trachea > bronchi > bronchioles > alveoli
- B. bronchioles > alveoli > bronchi > larynx > pharynx > lungs
- C. mouth/nose > bronchi > bronchioles > alveoli > lungs > trachea
- D. alveoli > bronchioles > lungs > bronchi > trachea > larynx > pharynx > mouth/nose
Correct Answer: A
Rationale: The correct path through which air moves during inhalation is from the mouth/nose > pharynx > larynx > trachea > bronchi > bronchioles > alveoli. This sequence accurately represents the typical route air takes as it travels from the external environment into the lungs to facilitate gas exchange in the alveoli. Choice B is incorrect as it reverses the order of bronchioles and alveoli. Choice C is incorrect as it starts with mouth/nose but then incorrectly lists lungs before trachea. Choice D is incorrect as it reverses the entire sequence of the respiratory pathway, starting with alveoli instead of mouth/nose.