Nokea
Which element's neutral atom has 2 electrons in the first shell and 6 electrons in the second shell of the electron cloud?
- A. Beryllium
- B. Carbon
- C. Helium
- D. Oxygen
Correct Answer: D
Rationale: The correct answer is Oxygen. Oxygen has a total of 8 electrons, with 2 in the first shell and 6 in the second shell. This configuration matches the description provided in the question. Choice A, Beryllium, has 2 electrons in total, so it cannot have 2 in the first shell and 6 in the second. Choice B, Carbon, has 6 electrons in total, so it also does not match the given electron distribution. Choice C, Helium, has only 2 electrons in total and therefore does not fit the electron configuration described in the question.
You may also like to solve these questions
How does the developing fetus primarily eliminate metabolic wastes?
- A. The developing fetus does not produce metabolic wastes.
- B. Fetal waste is excreted as feces, which pass into the mother's anus.
- C. Fetal waste is passed down the umbilical cord to the mother's circulatory system.
- D. Fetal waste is passed down the umbilical cord and leaves the mother's body via the vagina.
Correct Answer: C
Rationale: Metabolic wastes produced by the developing fetus are eliminated primarily by being passed down the umbilical cord to the mother's circulatory system. Once in the mother's blood, these wastes are then filtered and excreted by the mother's kidneys. Choice A is incorrect because the developing fetus does produce metabolic wastes. Choice B is incorrect as fetal waste does not pass into the mother's anus. Choice D is incorrect as fetal waste does not leave the mother's body via the vagina.
During which phase of meiosis do chiasmata structures form?
- A. Prophase I
- B. Prophase II
- C. Metaphase I
- D. Metaphase II
Correct Answer: A
Rationale: Chiasmata structures, where crossing over occurs, form during Prophase I of meiosis. This phase is characterized by homologous chromosomes pairing up and crossing over, leading to the exchange of genetic material between non-sister chromatids. Chiasmata are visible points of contact where genetic material has been exchanged, and they play a critical role in genetic diversity. Prophase II is the phase where chromosomes condense again in the second meiotic division, but chiasmata formation occurs in Prophase I. Metaphase I is the phase where homologous chromosomes align at the metaphase plate, not where chiasmata form. Metaphase II is the phase where replicated chromosomes align at the metaphase plate in the second meiotic division, but chiasmata formation occurs earlier in Prophase I.
During which developmental process does the first trimester of gestation roughly correspond?
- A. Embryogenesis
- B. Fertilization
- C. Meiosis
- D. Menstruation
Correct Answer: A
Rationale: The correct answer is A: Embryogenesis. The first trimester of gestation involves the process of embryogenesis, where the basic structures of the embryo are formed. This period is critical for the development of major organ systems and the establishment of the embryo's overall body plan. Fertilization occurs at the beginning of pregnancy when the sperm fertilizes the egg, marking the start of embryonic development. Meiosis is a cell division process that produces gametes (sperm and egg cells) with half the number of chromosomes. Menstruation is the shedding of the uterine lining when pregnancy does not occur.
Which type of cells are found in the hair bulb and are responsible for hair growth?
- A. Basal
- B. Epidermal
- C. Epithelial
- D. Merkel
Correct Answer: C
Rationale: The correct answer is C: Epithelial. The hair bulb contains actively growing epithelial cells responsible for hair growth. Basal cells are located in the basal layer of the epidermis, not specifically in the hair bulb, making choice A incorrect. Epidermal cells are part of the outer layer of the skin, so choice B is incorrect. Merkel cells are related to touch sensations in the skin, not hair growth, making choice D incorrect.
Which part of the hair is not attached to the follicle?
- A. Bulb
- B. Root
- C. Shaft
- D. Strand
Correct Answer: C
Rationale: The correct answer is C, 'Shaft.' The hair shaft is the part of the hair that extends above the skin surface and is not attached to the follicle. The bulb and root are parts that are connected to the follicle as they are located below the skin surface and play a role in hair growth. The strand, on the other hand, refers to a single hair fiber and is not a distinct part of the hair anatomy.