"use strict"; ({ prompt: "The researchers only tested the irritants on adult human males. Which of the following statements gives the most likely reason for choosing only male subjects? Male and female epidermis have different:", explanation: "In general, male and female epidermis have different thickness, with male epidermis being thicker. This could cause a difference in the effect of irritants on the skin, so the researchers only chose adult human males to keep the epidermis thickness approximately constant.", itemType: "passageChooseOne", options: null, passage: "One of the most important functions of the cell is cell division. In this process, new cells are formed. All cells except for sexual cells carry out cell division by a process called _mitosis_, in which one parent cell produces two identical daughter cells.\n\nA group of scientists was studying cell division in the epidermis. The _epidermis_ is the outermost tissue of the body, and it is a barrier of entry for dangerous microorganisms. Studying cell division is important to assess the ability of the epidermis to self-heal and regenerate.\n\nScientists were studying the effect of some irritants on the mitotic response in the epidermis. The studied irritants were: dimethylacetamide (DMAC), 5% hydrochloric acid (HCl), 1% benzalkonium chloride (BACl), and 1% aqueous sodium lauryl sulfate (SLS). After applying these irritants to the skin of adult human males for a given period of time, the mitotic index (mitoses per thousand viable cells) was obtained. The results are shown in Table 1. An untreated control at time 0 h had a mitotic index of 0.94 ± 0.16.\n\n

Table adapted from Fisher, Louis B., and Howard I. Maibach. \"Effect of some irritants on human epidermal mitosis.\" _Contact Dermatitis_ 1.5 (1975): 273-276.
Table 1
Irritant	Mitotic index after time T
T = 24h	T = 48h	T = 96h
DMAC	0.13 ± 0.05	2.47 ± 0.61	0.89 ± 0.14
5% HCl	1.21 ± 0.16	1.35 ± 0.29	1.14 ± 0.24
1% BaCl	2.42 ± 0.32	1.59 ± 0.30	1.23 ± 0.16
1% SLS	2.51 ± 0.54	15.46 ± 3.70	9.33 ± 1.59

", answer: "thickness", distractors: ["meiosis rates", "mitosis rates", "cell division mechanisms"] });

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