Free Science Practice Test

Heart rates vary significantly among different species and can provide important insights into their biology and health. The heart rate of an animal is the number of times its heart beats per minute. Smaller animals typically have faster heart rates compared to larger animals. Scientists study heart rates to understand how different species manage energy and how their circulatory systems support their metabolic needs. The graph compares several animal species by both average heart rate and average body weight.

Of the species in this graph, which has the median body weight?

A) Pig

B) Sheep

C) Goat

D) Rabbit

This diagram shows a food web in a marine ecosystem, illustrating the interactions between various species. The web indicates the flow of energy from one organism to another, highlighting the dependencies and impacts different species have on each other.

Keep in mind that the arrows point from the prey to the predator.

Which of the following is true about this food web? Two answers are correct.

A. An increase in herring would increase zooplankton.
B. A decrease in codfish would increase herring.
C. An increase in seals would decrease codfish.
D. Phytoplankton eat both zooplankton and herring.

Photosynthesis is a vital process that allows plants to convert sunlight into energy. During photosynthesis, plants take in carbon dioxide from the air and water from the soil. Using the energy from sunlight, they convert these into glucose and oxygen. The glucose provides energy for the plant to grow and develop, while the oxygen is released into the atmosphere, which is essential for the survival of most living organisms on Earth.

The process of photosynthesis takes place in the chloroplasts of plant cells, which contain the pigment chlorophyll. This pigment captures sunlight and initiates the chemical reactions necessary for photosynthesis. Without photosynthesis, plants would not be able to produce the energy they need to survive, and oxygen levels in the atmosphere would decrease, affecting all aerobic life forms.

Scientists study photosynthesis to understand how plants adapt to different environmental conditions. By learning more about this process, researchers hope to develop new agricultural techniques that can improve crop yields and address food shortages. Additionally, understanding photosynthesis can help scientists find ways to reduce carbon dioxide levels in the atmosphere, combating climate change.

What conclusion can be drawn about the significance of photosynthesis based on the passage?

A. Photosynthesis takes place in the chloroplasts of plant cells.
B. Photosynthesis is crucial for producing oxygen and energy necessary for life.
C. Scientists study photosynthesis to develop new agricultural techniques.
D. Chlorophyll is the pigment that captures sunlight for photosynthesis.

In this experiment, you are provided with graphs depicting the growth of three different plant species as a function of light intensity. Two of the species demonstrate growth rates that increase with light intensity, suggesting a direct proportionality. The third species exhibits a decline in growth rate as light intensity increases, indicative of an inverse proportionality.

Which variable is the dependent variable in this experiment?

A. Growth of Plant

B. Light Intensity

C. Type of Plant

D. Duration of Experiment

The table below compares the charging times of three types of electric vehicles.

Based on the table, how many times faster is the Super Fast Charge EV compared to the Standard EV?

Options:
A. 8
B. 10
C. 16
D. 20

The dodo bird, an extinct flightless bird that lived on the island of Mauritius, disappeared in the late 17th century. The reasons behind its extinction have been debated among scientists, leading to two main hypotheses.

One group of scientists believes that human activities directly led to the extinction of the dodo. When humans first arrived on Mauritius in the late 16th century, they brought with them animals such as pigs, rats, and monkeys. These invasive species preyed on dodo eggs and competed for food resources. Additionally, humans hunted the dodo for food. The combined pressures from predation by invasive species and direct hunting by humans resulted in the rapid decline of the dodo population. Historical records from sailors and settlers describe hunting and capturing dodos, supporting this hypothesis.

Another group of scientists argues that environmental changes and habitat destruction were the primary causes of the dodo’s extinction. When humans settled on Mauritius, they cleared large areas of forest for agriculture and settlements. This deforestation led to significant habitat loss for the dodo, which relied on the forest for nesting and feeding. Pollen analysis from soil layers on Mauritius has shown a marked increase in grass pollen and a decrease in tree pollen around the time of the dodo’s extinction. These environmental changes would have severely impacted the dodo’s ability to survive, regardless of direct human predation.

Which piece of evidence from the passage supports the hypothesis that environmental changes were the primary cause of the dodo’s extinction?

A. Historical records describing hunting and capturing dodos.

B. The introduction of animals such as pigs, rats, and monkeys.

C. The marked increase in grass pollen and decrease in tree pollen around the time of the dodo’s extinction.

D. Fossils of dodos showing signs of malnutrition and disease.

Traits are inherited through genes, the memory banks of the cell. Every gene has two versions, called alleles. We use capital letters for dominant alleles (A) and lowercase for recessive alleles (a). In cats, the long-haired trait (A) is dominant over the short-haired trait (a).

Read the scenario and answer the question.

One cat carries heterozygous long-haired traits (Aa), and its mate carries homozygous short-haired traits (aa).

Use the Punnett square to determine the probability of one of their offspring having long hair.

One way to determine the age of ancient artifacts is to measure the ratio of certain radioactive elements to their more stable forms. This technique, known as radiometric dating, relies on the fact that radioactive isotopes decay at a predictable rate over time. By analyzing the remaining amount of the radioactive element and its stable decay product in a sample, scientists can calculate how long the decay process has been occurring, thus estimating the age of the artifact.

Carbon-14 dating is a well-known example of radiometric dating, commonly used for organic materials like wood and bone. This method measures the ratio of radioactive carbon-14 to stable carbon-12 in the sample. However, carbon-14 dating has limitations, as its accuracy diminishes for samples older than about 50,000 years due to the relatively short half-life of carbon-14.

For older materials like rocks and minerals, other radiometric dating methods, such as uranium-lead dating or potassium-argon dating, are employed. These methods utilize isotopes with much longer half-lives, enabling scientists to date objects billions of years old.

While radiometric dating is a powerful tool for determining the age of artifacts, it is important to note that it provides an estimate rather than an exact age. Factors such as contamination or changes in environmental conditions can affect the accuracy of the dating process.

According to the passage, what is a key principle underlying radiometric dating?

A) The ratio of radioactive elements to stable forms remains constant over time.
B) Radioactive isotopes decay at a predictable rate.
C) Carbon-14 dating is the most accurate method for all types of artifacts.
D) Radiometric dating provides the exact age of an artifact.

The term solubility refers to the amount of a substance (solute) that will dissolve in a given amount of a liquid substance (solvent). The solubility of solids in water varies with temperature. The graph below displays the water solubility curves for five crystalline solids.

The graph shows the solubility of five different crystalline solids in water, measured in grams of solute per 100 mL of water, across a range of temperatures from 0°C to 90°C. Each line represents a different substance and indicates how its solubility changes with temperature.

Substances in the Graph:

1. CaCl₂ (Calcium Chloride)
2. MgSO₄ (Magnesium Sulfate)
3. KCl (Potassium Chloride)
4. Li₂CO₃ (Lithium Carbonate)
5. Na₂SO₄ (Sodium Sulfate)

Based on the graph data, which of the following substances has the greatest change in solubility as temperature increases?

A. CaCl₂ (Calcium Chloride)
B. MgSO₄ (Magnesium Sulfate)
C. KCl (Potassium Chloride)
D. Na₂SO₄ (Sodium Sulfate)

The blood type is determined genetically—each person inherits it from their parents. As it is controlled by a single gene, each person has two alleles describing their blood group:

• Blood type A: either AA or AO
• Blood type B: either BB or BO
• Blood type AB: alleles AB
• Blood type O: alleles OO

Alleles A and B are dominant, and allele O is recessive. Only people with OO alleles can have the blood type O.

Read the scenario and answer the question.

A woman with type AO blood claims that a man with type AB blood is the father of her child, who has type A blood. Is it possible?