ACT Science Practice Test 88

I appreciate you providing this content, but I need to clarify what I'm seeing: The PASSAGE section contains: 1. A fragment of unrelated text ("ther steered and becoming the first 'accidental' president to potentially rivals.") 2. A scientific figure (a graph showing atmospheric composition over time with H₂O and O₂ levels) The QUESTIONS section contains 12 questions (Q1-Q12) that reference "Solutes," "Mixtures," and data interpretation—none of which correspond to the passage text provided. **This doesn't match the ACT English format I'm designed to handle.** The ACT English section presents continuous prose passages with underlined portions and multiple-choice grammar/style questions. What you've provided appears to be either: - Science/Data Interpretation questions (from ACT Science) - Incomplete or mismatched passage/question sets **To help you properly, I need:** 1. A complete prose PASSAGE with underlined portions marked by standalone digits 2. QUESTIONS that correspond to those underlined portions with options like "NO CHANGE" and alternative phrasings Could you provide the correct passage and matching questions?

Simple diffusion (SD) is the process by which an uncharged solute in water migrates directly across an uncharged membrane, while facilitated diffusion (FD) is the process by which a charged or polar solute travels through a channel or transporter that crosses the membrane. Figure 1 illustrates how two solutes can diffuse, one by SD and one by FD.

Figure 1

Solutes that cross a membrane by SD or by FD show different rates of flow across a membrane, also known as flux. As a solute crosses a membrane by SD, the flux follows a linear pattern over time, with smaller solutes having the greatest increase in flux over time. As a solute crosses a membrane by FD, the flux follows a logarithmic pattern, leveling off at a maximum flux since there are only a limited number of channels or transporters through which the solute can travel.

Experiment 1

One scientist introduced five different solutes of the same concentration to similar membranes at a constant temperature. The molecular masses of these solutes are shown in Table 1.

Table 1
Solute	Molecular mass (amu)
#1	160
#2	800
#3	2,000
#4	10,000
#5	40,000

This scientist then measured the time it took for the solute to reach equilibrium, which is a state of equal concentration of the solute on both sides of the membrane. The results are shown in Figure 2.

Figure 2

Experiment 2

Mixtures of solutes are subsequently introduced near three different membranes with different properties. The results of these three trials are presented in Figure 3.

Figure 3

The term "evolution" is often used in the context of biological changes in organism populations over time, but it can also be applied to the change in the chemical composition of the Earth's atmosphere. The hypotheses of two studies claim that this chemical evolution has altered the types of chemicals found in the atmosphere between the early stages of Earth's existence and the present day.

Study 1

Based on the hypothesis that volcanic eruptions were the source of gases in the early Earth's atmosphere, scientists recreated four model volcanic eruptions in closed chambers, each containing different percentages of the same volcanic particulate matter. They then observed the gases in the air above this model over time. The percent composition of this air after 1 day, when the air achieved a steady state of constant gas concentrations, is represented in Table 1.

Since the experiment provided only a suggestion of the gas levels in the early Earth's atmosphere, the scientists then analyzed the amount of trapped gases in sediment layers, which indicate the changing atmospheric levels of gases over billions of years. The data collected on O₂ and H₂O vapor are presented in Figure 1.

Study 2

A separate study used the same volcanic models as in Study 1, but it hypothesized that the scientists in Study 1 underestimated the amount of H2 in the early Earth atmosphere. They proposed a different composition of gases, highlighting an increased H₂ level in the atmosphere, also represented in Table 1. Based on these new data, the scientists proposed an alternative graph for the changing atmospheric levels of O₂ and H₂O vapor, also shown in Figure 1.

Figure 1

Science practice 67