Science Mid-term Exam – Grade 4

Vertebrates are animals that do have a backbone. This distinguishes them from invertebrates, which do not have a backbone. Therefore, the correct answer is False.

Fish breathe through gills, which are specialized organs that extract oxygen from water. Gills are located on the sides of a fish's head and consist of thin filaments that are rich in blood vessels. As water passes over the gills, oxygen is extracted from the water and absorbed into the fish's bloodstream, while carbon dioxide is released. This allows fish to extract oxygen from their aquatic environment and survive underwater.

A food chain is a representation of the flow of energy in an ecosystem, showing how energy is transferred from one organism to another as they consume each other. Each organism in the chain serves as a source of energy for the next organism in line. This transfer of energy is essential for the survival and functioning of the ecosystem. Therefore, the statement "A food chain shows the transfer of energy from one organism to another" is true.

Mammals are warm-blooded animals, meaning they can regulate their body temperature internally. Unlike cold-blooded animals such as fish, amphibians, and reptiles, mammals have the ability to generate and maintain their own body heat through metabolic processes. This allows them to live in a wide range of environments and climates.

Animal cells do not have a cell wall. Instead, they are surrounded by a flexible and permeable plasma membrane. The cell wall is a characteristic feature of plant cells and some other organisms, providing structural support and protection.

Bacteria are actually unicellular organisms, meaning they are made up of a single cell. They do not have specialized cells or tissues that make up a multicellular organism. Bacteria reproduce by dividing into two identical cells, and each individual cell is capable of carrying out all necessary functions for survival. Therefore, the statement that bacteria are multicellular is incorrect.

The Ascaris worm is an example of a roundworm. Roundworms, also known as nematodes, are a type of worm that have a long, cylindrical body shape. They are found in various environments, including soil, water, and the bodies of animals and humans. Ascaris worms are one of the most common types of roundworms that infect humans. They typically live in the intestines and can cause symptoms such as abdominal pain, diarrhea, and weight loss.

Living organisms possess various attributes or characteristics that distinguish them from non-living things. These attributes include the ability to grow, reproduce, respond to stimuli, adapt to their environment, and maintain homeostasis, among others. Therefore, it is accurate to say that attribute is indeed one of the characteristics of living organisms.

Reptiles are not invertebrates because they have a backbone or vertebral column, which classifies them as vertebrates. In contrast, sponges, echinoderms, and mollusks are all examples of invertebrates as they lack a vertebral column and are characterized by their soft bodies.

Grasslands are moderately cold in winter and warm to hot in summer, with moderate rainfall, and fertile soil. This type of region is characterized by the presence of grasses and few to no trees. The moderate climate allows for the growth of grasses, while the fertile soil supports their growth. The moderate rainfall ensures that there is enough water for the grasses to thrive. Overall, grasslands provide a suitable environment for a variety of plant and animal species to flourish.

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The explanation for the given correct answer is not available.

Fungi are heterotrophs with cell walls and most feed on dead or decaying organic matter. This means that they obtain their nutrients by breaking down and absorbing organic material from their environment. Fungi play a crucial role in decomposition and nutrient cycling, as they break down complex organic compounds into simpler forms that can be used by other organisms. Their cell walls provide structural support and protection, similar to the cell walls found in plants. Overall, fungi are essential organisms in ecosystems due to their role in recycling nutrients and breaking down organic matter.

A population refers to a group of individuals that belong to the same species and live in the same area. It represents the total number of organisms of a particular species in a given location. This term specifically focuses on the number of individuals, rather than the interactions between different species or the physical environment. Therefore, population is the most appropriate answer in this context.

Non-seed plants refer to plants that do not produce seeds for reproduction. These plants reproduce through spores or other means, such as fragmentation or vegetative propagation. Examples of non-seed plants include mosses, ferns, and algae. These plants have a different reproductive strategy compared to seed plants, which rely on the production and dispersal of seeds for reproduction. Non-seed plants are typically found in moist environments and play important roles in ecosystems as they contribute to soil formation, provide habitats for various organisms, and contribute to the overall biodiversity of the planet.

Carbon dioxide is a colorless and odorless gas that is produced by the combustion of fossil fuels and the respiration of living organisms. It is a greenhouse gas that contributes to climate change and global warming. Additionally, carbon dioxide is also used in various industrial processes such as carbonation of beverages and as a fire extinguishing agent.

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Scientists classify plants into two main groups: seed plants and seedless plants. Seed plants are those that reproduce through the formation of seeds, which contain the embryo and provide protection and nourishment. Seedless plants, on the other hand, do not produce seeds but reproduce through spores or other methods. This classification is important as it helps in understanding the reproductive strategies and evolutionary relationships among different plant species.