Science Review 1.5

Bacteria are a type of microorganism. They are found in the environment and in food. They are also found inside people and animals. Touching a surface with bacteria can spread them from one place to another.

Bacteria break down food for digestion. Cows are able to digest grass because of bacteria. Bacteria can also alter food. Bacteria turn milk into other dairy products, like yogurt and cheese. Sourdough bread tastes sour because of bacteria.

Some types of bacteria produce toxins. These types of bacteria can cause illnesses. Eating foods with certain bacteria can cause stomach cramps. Bacteria also cause plaque buildup on teeth. These bacteria can lead to gum disease and cavities. Which bacteria function proves that some microorganisms are harmful?

• giving bread a sour taste

• breaking down food for digestion

• turning milk into yogurt and cheese

• producing plaque that causes gum disease

Students are learning the difference between inherited and acquired traits in their science class. Traits are characteristics that can be physical or behavioral. Inherited traits are passed down from parents to offspring. Acquired traits are learned through interactions in the environment. The image shows a few examples of inherited and acquired traits. A student has dimples on their cheeks. Which question would BEST determine if the dimples are an inherited trait?

• What size are the dimples?

• Do other students have dimples?

• Does the student like their dimples?

• Was the student born with dimples?

Students are learning the difference between inherited and acquired traits in their science class. Traits are characteristics that can be physical or behavioral. Inherited traits are passed down from parents to offspring. Acquired traits are learned through interactions in the environment. The image shows a few examples of inherited and acquired traits. A student has enjoyed dancing for as long as they can remember and is very good at it. Which question would BEST classify the student's dancing abilities as acquired?

• Was the student born with the ability to dance?

• Did the student take lessons to learn to dance?

• Is the student a better dancer than their parents?

• Did the student inherit the ability to dance from their parents?

A volcanic eruption occurs when magma and gases break through Earth's surface. When the magma explodes onto Earth's surface, it becomes lava and cools down. The cooled lava often creates a landform known as a volcano. In New Mexico, a volcanic eruption occurred 30 million years ago. Over time, natural forces changed the volcano and the area around it. Today, the volcano is extinct because it no longer erupts. A landform called Shiprock is all that is left. The area and the landform are shown. Which process broke down the rock of the original volcano?

• erosion

• deposition

• weathering

• sedimentation

A volcanic eruption occurs when magma and gases break through Earth's surface. When the magma explodes onto Earth's surface, it becomes lava and cools down. The cooled lava often creates a landform known as a volcano. In New Mexico, a volcanic eruption occurred 30 million years ago. Over time, natural forces changed the volcano and the area around it. Today, the volcano is extinct because it no longer erupts. A landform called Shiprock is all that is left. The area and the landform are shown. Which process MOST LIKELY transported the broken-down rock away from the volcano?

• erosion by wind

• deposition by wind

• erosion by organisms

• weathering by organisms

What is a difference between bar magnets and electromagnets?

• Electromagnets need a power source and bar magnets do not.

• Electromagnets can attract metal objects and bar magnets cannot.

• Bar magnets have adjustable strengths and electromagnets have fixed strengths.

• Bar magnets are temporary magnets and electromagnets are permanent magnets.

A student finds a plant growing on the trunk of a pine tree. The student makes the following model of what he saw. Which statement BEST classifies each plant?

• The pine tree is an angiosperm, and the plant on the tree's trunk is a fern.

• The pine tree is a gymnosperm, and the plant on the tree's trunk is a fern.

• The pine tree is a gymnosperm, and the plant on the tree's trunk is a moss.

• The pine tree is an angiosperm, and the plant on the tree's trunk is a moss.

Probiotics are live microorganisms like yeast and bacteria. There are many foods that contain probiotics, as seen in the image. The human digestive system has lots of natural bacteria in it. Probiotics can be the same, or similar, to the microorganisms naturally found in the human digestive system. People with digestive system issues are often told by their doctors to eat food with lots of probiotics. Probiotics can balance the microorganisms in the human body, influence the immune system, aid in digesting food, and produce vitamins. A child has digestive issues. The doctor tells the child's parent to give them yogurt for breakfast each morning. How can yogurt help the child's digestive issues?

• Yogurt contains bacteria that strengthen the immune system.

• Yogurt is soft, so it can easily move through the digestive system.

• Yogurt contains lots of vitamins that are healthy for the immune system.

• Yogurt can restore the beneficial microorganisms in the digestive system.

The table shows the population of beneficial microorganisms in a human digestive system. The population was recorded before an illness, after an illness, and then again after probiotics were eaten following the illness. Which statement BEST describes the effect of the probiotics on the beneficial microorganism population?

• The probiotics had no effect on the population of beneficial microorganisms present after the illness.

• The probiotics restored the population of beneficial microorganisms to what it was before the illness.

• The probiotics decreased the population of beneficial microorganisms to less than it was before the illness.

• The probiotics increased the population of beneficial microorganisms to more than it was before the illness.

Students learn about physical changes in their science class. A physical change occurs when the appearance or form of a substance changes, but a new substance is not created. When a substance undergoes a physical change, it can be changed back into its original form.

The students’ teacher gives them each colored paper, scissors, and markers. Then, the teacher gives each student instructions to create an origami animal by using the supplies. The students fold, cut, and draw on the colored paper and create the origami animals. Some of the completed origami animals are shown in the image. A student cuts a piece of paper into tiny pieces. Is this an example of a physical change?

• No, because the tiny pieces of paper are new substances.

• Yes, because the tiny pieces of paper are new substances.

• No, because the tiny pieces of paper are still the original substance

• Yes, because the tiny pieces of paper are still the original substance.