Science Mixed Practice Test 6

Where the answer comes from: the passage says "The farther away the station is, the longer the time between the two arrivals," and "each second of S–P interval means the epicenter is about 8 km away." The table gives Brook 12 s (96 km) and Corley 40 s (320 km); Ashford's interval is 25 s.

Step by step:

1. Find Ashford's distance: 8 km for each second of lag, so 25 \times 8 = 200 km.
2. Compare the distances: Brook 96 km, Ashford 200 km, Corley 320 km.
3. The smallest distance (and the shortest S–P interval, 12 s) belongs to Brook.

The closest station is Brook, about 96 km away.

Check: 12 \times 8 = 96 ✓, which matches the table.

Tip: In S–P questions, shorter gap = closer. Do not mix up the seconds column with the kilometers column.

Where the answer comes from: the passage says water "escapes into the air as water vapor through tiny pores, a process called transpiration." The leafy bag collected 4.2 mL, while the bag around a bare stick collected only 0.3 mL.

Step by step:

1. The bag was sealed, so no rain could get in. That rules out precipitation.
2. The leafy branch is the only source that the bare-stick bag did not have.
3. Water traveled from the roots up to the leaves and left the leaves as vapor: transpiration.
4. The vapor then condensed into droplets on the cooler inside of the bag. Condensation formed the droplets, but transpiration supplied the vapor.

The answer is transpiration.

Check: The extra water in the leafy bag is 4.2 - 0.3 = 3.9 mL, which came from the plant ✓.

Tip: Read the question's exact wording. Put vapor into the bag asks for the source of the vapor, not how the droplets formed.

Where the answer comes from: the passage says "The Moon's orbit is tilted about 5° compared with Earth's orbit around the Sun. So in most months, the new moon passes a little above or below the Sun." Eclipses happen "only when a new or full moon occurs near one of the two points where the Moon's orbit crosses the plane of Earth's orbit."

Step by step:

1. A solar eclipse needs the Moon directly between the Sun and Earth.
2. Every new moon, the Moon is roughly between them, but because of the 5° tilt it usually passes a little above or below the Sun–Earth line.
3. Then the Moon's shadow misses Earth, so there is no eclipse.
4. Only when new moon happens near a crossing point does the shadow land on Earth.

The answer is the Moon's orbit is tilted about 5°, so at most new moons its shadow passes above or below Earth.

Tip: Do not confuse the Moon's 5° orbital tilt (eclipses) with Earth's 23.5° axis tilt (seasons). Match the number to the topic.

Evidence: the table shows core temperature of 37.0 °C at 0 minutes and 37.5 °C at 45 and 60 minutes, while the room was 40 °C. Skin temperature went from 33.0 °C to 36.3 °C over the same time.

Step by step:

1. Change in core temperature in the hot room: 37.5 - 37.0 = 0.5 °C. That is a small change.
2. Change in skin temperature: 36.3 - 33.0 = 3.3 °C, more than six times as much.
3. The room was 40 °C, yet the core never got close to 40 °C. The body held its inside temperature in a narrow range. That is homeostasis, helped by sweating, which the passage says carries heat away.
4. Eliminate B (the core stayed far below 40 °C), C (the skin changed more, not the core), and D (0.5 °C is a small change, but it is a change).

The answer is A.

Tip: homeostasis questions usually show one number that barely moves while the conditions around it change a lot. Compare the size of the changes before you decide.

Evidence: paragraph 1: "Antibiotics do not work against viruses, which cause colds and flu, because viruses are not cells and do not have the cell parts that antibiotics attack."

Step by step:

1. A cold is caused by a virus.
2. Antibiotics attack parts of bacterial cells. Viruses are not cells and lack those parts.
3. So even the antibiotic that worked best against these bacteria (22 mm) would not help a cold.
4. Eliminate B (X actually worked best in the test), C (the 37 °C was a lab condition, not a rule about where antibiotics work), and D (colds are caused by viruses, not bacteria).

The answer is A.

Tip: a strong result in one test only applies to what was tested. These dishes held bacteria, so the results say nothing about viruses.

Where the answer comes from: the table shows type O has only the genotype i\,i. Type AB has only the genotype I^A I^B.

Step by step:

1. The child is i\,i, so she received one i from her mother and one i from her father.
2. The mother (type A) must be I^A i, which is possible.
3. The father must carry at least one i. Check each type:
   • Type A: I^A i is possible ✓
   • Type B: I^B i is possible ✓
   • Type O: i\,i ✓
   • Type AB: I^A I^B has no i ✗

Answer: type AB.

Check: a type AB father would give every child either I^A or I^B, so none of his children could have type O.

Tip: in work-backwards problems, start with the offspring whose genotype is certain (a recessive phenotype like type O), then ask what each parent must carry.

Where the answer comes from: the graph gives these values: 2000: 5; 2004: 10; 2008: 22; 2012: 38; 2016: 46; 2020: 48.

Step by step: subtract for each 4-year period.

• 2000–2004: 10 - 5 = 5 points
• 2004–2008: 22 - 10 = 12 points
• 2008–2012: 38 - 22 = 16 points
• 2012–2016: 46 - 38 = 8 points
• 2016–2020: 48 - 46 = 2 points

Answer: 2008 to 2012.

Check: on the graph, the segment from 2008 to 2012 is the steepest part of the line, which matches the largest change.

Tip: "increased the most" asks about the change during a period, not the highest value. The highest value (48) is in 2020, but the line was almost flat by then.

Evidence: The graph shows the sand rising 7 °C every 2 minutes (20, 27, 34, 41, 48, 55 °C) and the water rising 2 °C every 2 minutes (20, 22, 24, 26, 28, 30 °C). Both patterns are straight lines.

Step by step:

1. Sand at 10 min: 55 °C. One more 2-minute step adds 7 °C: 55 + 7 = 62 °C.
2. Water at 10 min: 30 °C. One more 2-minute step adds 2 °C: 30 + 2 = 32 °C.
3. Check the pairing: the sand must stay the hotter of the two, because it warms faster.

The best prediction is sand about 62 °C, water about 32 °C.

Check: Using per-minute rates gives the same result: sand 3.5 \times 12 = 42 °C above 20 °C, so 62 °C; water 1 \times 12 = 12 °C above 20 °C, so 32 °C.

Tip: To extend a straight-line trend, find the steady change per step and add one more step. Keep each series separate so you do not swap them.

Evidence: Part 2 says the cube has "a mass of 158 g," and the water level rose from "40.0 mL" to "60.0 mL." It also says "1 mL = 1 cm³," and the reference table lists iron at 7.87 g/cm³.

Step by step:

1. Volume by displacement: 60.0 - 40.0 = 20.0 mL = 20.0 cm³.
2. Density: D = \frac{m}{V} = \frac{158\text{ g}}{20.0\text{ cm}^3} = 7.9\text{ g/cm}^3
3. Compare with the table: aluminum 2.70, zinc 7.14, iron 7.87, lead 11.34. The value 7.9 is closest to iron (7.87).
4. Why this works: density is a physical property, so every sample of iron has the same density no matter its size.

The cube is most likely iron.

Tip: In displacement problems, the object's volume is the change in the water level, not the final reading. Using 60.0 mL gives 158 \div 60 \approx 2.6 g/cm³, which wrongly points to aluminum.

Evidence: The chart lists asparagus at "6.5 to 7.5" and Ana's soil at "4.8." The passage says garden lime "is a base, so mixing it into soil neutralizes some of the acid and raises the pH," while sulfur "lowers the pH."

Step by step:

1. Ana's soil (4.8) is below the asparagus range (6.5 to 7.5), so she needs to raise the pH.
2. Raising pH means making the soil less acidic, which a base does by neutralizing acid.
3. Garden lime is a base and raises the pH. Sulfur would lower it further, the wrong direction.

The answer is Mix garden lime into the soil to raise the pH.

Check: Moving from 4.8 toward 6.5–7.5 means moving toward neutral (7), which is what neutralization does.

Tip: To raise pH, add a base. To lower pH, add an acid (or something that forms an acid). Neutralization always moves pH toward 7.

The friend extended the pattern: 20 + 1.2 \times 120 = 164%. The arithmetic is correct, but the passage defines the battery level as "a percent of a completely full battery (100%)." A battery cannot hold more than a full charge.

Step by step:

1. The steady pattern only describes the first 40 minutes.
2. At 1.2 points per minute, the battery would reach 100% after \dfrac{80}{1.2} \approx 67 minutes.
3. After that the level cannot keep rising; it stays at 100% (most phones also charge more slowly as they get close to full).

The correct answer is the level cannot go above 100%, so the straight-line pattern must stop once the battery is full.

Check: Any prediction above 100% contradicts the passage's own definition of the measurement.

Tip: Extrapolation is risky when it runs into a natural limit — 100% full, a boiling point, a food supply, or space in a container. Ask whether the answer is even possible.

Where the answer comes from: the table header "| Ramp height (cm) | Average distance rolled (cm) |" names both variables and their units.

Step by step:

1. The question says ramp height goes on the horizontal axis, so distance goes on the vertical axis.
2. Each label should name the variable clearly and give its unit in parentheses: centimeters for both.
3. "Height" and "Distance" with no units leave a reader guessing whether the numbers are inches, centimeters or meters.
4. Swapping the labels contradicts the plan, and "seconds" is not a unit of distance.

Correct answer: C.

Check: read the label back with a value: "Ramp height: 30 cm; Average distance rolled: 160 cm." It makes sense, so the labels work.

Tip: On the GED, the best axis label is specific (what was measured) and includes units. Missing or wrong units are the most common trap.

Where the answer comes from: "She worked slowly so the air stayed at room temperature, 22 °C."

Step by step:

1. The student changed the pressure on purpose (independent variable).
2. She measured the volume (dependent variable).
3. She worked slowly so the temperature stayed the same. A factor kept the same so it cannot affect the results is a controlled variable.
4. A hypothesis is a testable prediction, not a variable.

Correct answer: D.

Check: if temperature had changed, the air volume could have changed for that reason too, and the student could not tell which factor caused the change. Keeping it constant prevents that.

Tip: Look for phrases like "kept the same," "stayed at" or "the same for every trial". They signal controlled variables.

Where the answer comes from: the passage says the first student "placed 10 quadrats at random locations." Random placement gives every part of the field an equal chance to be sampled. The second student chose only the thickest patch.

Step by step:

1. Quadrats in the thickest corner will contain more plants than average — perhaps 8 or 10 instead of 4.
2. A higher mean per m² multiplied by the same 500 m² gives a larger total.
3. So the estimate would most likely be too high. This kind of error is called sampling bias.
4. Keeping the number of quadrats at 10 does not fix the problem; the issue is where they were placed, not how many.

Correct answer: B.

Tip: A sample must represent the whole population. Non-random sampling (choosing the easiest, closest or most interesting spots) produces biased estimates.

Evidence: The stem says the spacecraft is "far out in empty space" and the engine "forces hot exhaust gas out of the back."

Step by step:

1. Newton's third law: when one object pushes on another, the second pushes back with an equal and opposite force.
2. The spacecraft (its engine) pushes the exhaust gas backward.
3. The exhaust gas pushes the spacecraft forward with a force of equal size.
4. That forward force is an unbalanced force on the spacecraft, so it speeds up (Newton's second law).
5. Empty space has no air, so "pushing against the air" cannot be the reason. Rockets actually work best in a vacuum.

The answer is The spacecraft pushes the exhaust backward, and the exhaust pushes the spacecraft forward with an equal force.

Check: You can feel the same effect when you let go of an untied balloon: air rushes out one way and the balloon shoots the other way.

Tip: For any "how does it move forward?" question, find what the object pushes backward. Swimmers push water, walkers push the ground, rockets push exhaust.