In the nature center, we looked for animals that use camouflage. Camouflage helps an animal blend in with its surroundings so it can hide from predators or sneak up on prey. A green frog resting on lily pads was almost invisible. Its speckled skin matched the leaves and water. Our guide asked us to stand still and notice how the patterns and colors made the frog hard to spot. We learned that camouflage is a survival strategy many creatures share, from insects to birds to fish.

What does camouflage mean in this passage?

Earth spins once each day, giving us day and night. It spins around its axis, an imaginary line that runs through the North Pole and South Pole. Because Earth is tilted on this axis, different parts of the planet receive sunlight at different angles. That tilt helps create our seasons. If Earth did not have this tilt, the weather would be more the same all year. Globes show the axis with a small rod, but in space the line is just an idea to help us understand Earth's spin.

What does the word "axis" most likely mean in this passage?

On the grassland, a cheetah scans the tall grass. The cheetah is a predator, an animal that hunts other animals for food. Its sharp eyes and fast legs help it chase prey, like gazelles. Predators keep the ecosystem in balance by removing weak or sick animals. Without them, certain animal groups might grow too large and run out of plants to eat. Not all hunters use speed. Owls hunt at night and rely on silent wings. Whether fast or quiet, a predator must find food to survive.

What does the word "predator" most likely mean in this passage?

On the grassland, a hawk circles high above, searching carefully. The hawk is a predator, an animal that hunts other animals for food. It watches for small movements in the grass, then dives swiftly toward a mouse. Predators help keep animal groups in balance by eating the weak or the sick. Without them, some animals might eat too many plants. The mouse tries to hide in a burrow, but the hawk's sharp eyes and claws give it an advantage.

What does the word 'predator' mean in this passage?

At the museum, our class saw an artifact in a glass case. The sign explained it was a clay bowl made by people hundreds of years ago. An artifact is an object that people created in the past, not a rock or a bone formed by nature. The bowl had simple patterns and small chips on the rim. Our guide said it helped historians learn how families once cooked and ate. We imagined the maker shaping the clay with careful hands by a fire.

What does the word 'artifact' mean in this passage?

Each autumn, many birds migrate. When the air grows chilly and food becomes scarce, they travel long distances to warmer places. Geese form a V shape in the sky and fly south together, resting on lakes along the way. In spring, they return to their nesting grounds. This journey helps them find enough food and safe places to raise their young. Scientists track their paths to learn how weather affects their trips. Some birds even cross oceans during this seasonal move.

What does the word 'migrate' most likely mean as used in the passage?

After the rain, small puddles dotted the playground. By afternoon, many had started to evaporate. The warm sun heated the water, and it changed into an invisible gas that rose into the air. That is why the pavement looked dry again. This process happens faster on windy, sunny days and slower when it is cool and shady. When water evaporates from lakes and oceans, it later forms clouds that can bring rain back to the ground.

What does the word 'evaporate' most likely mean as used in the passage?

After a rainstorm, our class visited the river to watch how the water moved. We dropped tiny leaves and saw them glide downstream. The current was strong that day. The current, or the flow of water, pushed the leaves quickly around bends and past smooth stones. We stood on the bank and noticed calmer spots near the edge where the current slowed. In those places, the leaves drifted instead of zipping by. We wrote notes about how fast the current carried light things compared to heavy pebbles.

What does "current" mean in this context?

In our class library, I found a series about explorers. I picked the second volume and started reading from where the first book left off. In this passage, volume means one book in a set or series. The stories connect, so reading the volumes in order helps the adventures make sense. At first I thought about volume as loudness, like turning up the sound. But here, the nearby words show it is about books. The next day, I returned the second volume and checked out the third.

What does the word "volume" most likely mean in this passage?

During our sink-or-float experiment, we tested which objects were dense. In our investigation, dense meant packed closely together, so the heavy block sank quickly. A sponge, which was full of tiny air spaces, floated at first. When it filled with water, it slowly dropped lower. We compared a clay ball to a clay boat. The clay had the same mass, but the boat's shape spread it out. That made the boat less dense overall, and it stayed on top of the water.

What does dense mean in this passage?