ACT - Science Prep #1

An aquatic plant was placed under various light intensities. At 100 lux, the plant released 5 oxygen bubbles per minute. At 500 lux, it released 20 bubbles per minute. What is the approximate increase in the photosynthesis rate between 100 lux and 500 lux?

• 5 bubbles/min

• 12 bubbles/min

• 15 bubbles/min

• 20 bubbles/min

A student tested how different fertilizer concentrations affect the growth of tomato plants over two weeks. The plants grew 2 cm with no fertilizer, 10 cm with 3% fertilizer, but only 9 cm with 4% fertilizer. What conclusion can best be drawn from this experiment?

• Higher fertilizer always leads to more plant growth

• Fertilizer has no effect on plant growth

• Plant growth increases up to a certain concentration, then decreases

• Maximum growth occurs without any fertilizer

Scientists measured enzyme activity at various temperatures. The enzyme showed its highest reaction rate at 40°C, but the rate decreased at 50°C. At which temperature was the enzyme most active?

• 20°C

• 30°C

• 40°C

• 50°C

An enzyme’s reaction rate increased steadily as the temperature rose from 10°C to 40°C. At 50°C, the reaction rate dropped. What does this suggest about the enzyme’s activity beyond 40°C?

• The enzyme becomes more efficient at higher temperatures

• The enzyme’s activity decreases due to possible denaturation

• The enzyme continues to speed up the reaction

• Temperature has no effect on the enzyme

Two students are debating the Moon’s geologic history. Student 1 believes the Moon has no internal heat and is geologically inactive. Student 2 believes the Moon still has internal heat and experienced volcanic activity in recent geologic time. Which statement would both students most likely agree on?

• The Moon is currently volcanically active

• The Moon has always been geologically inactive

• Most of the Moon’s surface features are due to ancient impacts

• The Moon has never had volcanic activity