Grade 7th Science Online Test

There is a great variety of plants found on Earth, which includes thousands of different species. This diversity can be observed in various ecosystems, ranging from rainforests to deserts. Plants play a crucial role in maintaining the balance of ecosystems and providing habitats for other organisms. They also contribute to the production of oxygen and the absorption of carbon dioxide, making them essential for the survival of life on Earth. Therefore, it is true that a great variety of plants is found on the Earth.

Desert plants are adapted to survive in arid environments with limited water availability. One of the adaptations they have is being leafless or having reduced leaves. This helps to minimize water loss through transpiration, as leaves are the main site of water evaporation in plants. Instead, these plants often have thick, fleshy stems or modified leaves that store water. Therefore, the statement "Desert plants are either leafless" is true, as many desert plants have evolved to reduce or eliminate their leaves as a water-saving mechanism.

Desert plants have adapted to survive in arid environments by either being leafless or having leaves that are like small needles. This helps them to reduce water loss through transpiration and conserve water. Leafless plants, such as cacti, have evolved to store water in their stems, while plants with small needle-like leaves, such as certain types of succulents, have reduced surface area to minimize water loss. This adaptation allows desert plants to thrive in harsh conditions where water is scarce.

Coniferous trees like pine and deodar are well adapted to snowy regions like Kashmir because they have certain characteristics that enable them to thrive in such conditions. These trees have needle-like leaves that reduce water loss, allowing them to conserve moisture during the cold and dry winters. Additionally, their branches are designed to shed snow easily, preventing the accumulation of heavy snowfall that could damage the tree. The pine tree, specifically, is known for its ability to withstand cold temperatures and grow in nutrient-poor soils, making it a suitable choice for snowy regions like Kashmir.

Plants require essential nutrients such as nitrogen, phosphorus, and potassium for their growth. Nitrogen is necessary for the development of proteins, enzymes, and chlorophyll. Phosphorus is essential for energy transfer and the formation of DNA and cell membranes. Potassium plays a vital role in water regulation, nutrient transportation, and overall plant development. Therefore, it is true that plants need nitrogen, phosphorus, and potassium for their growth.

Fungi do not contain chlorophyll, which means they are unable to perform photosynthesis and make their own food like plants do. Instead, fungi obtain nutrients by breaking down organic matter in their environment. Therefore, the correct answer is False.

Deserts are characterized by severe lack of water. This means that deserts receive very little rainfall and have limited water sources such as rivers, lakes, or underground aquifers. The arid climate and high temperatures in deserts result in rapid evaporation, causing water to be scarce. This scarcity of water is a defining characteristic of deserts, making it the correct answer.

Coniferous trees like pine and deodar do not flourish in grasslands. They are typically found in forests, especially in regions with cooler climates. Grasslands, on the other hand, are characterized by the presence of grasses and other herbaceous plants, rather than trees. Therefore, the statement is false.

The odd-man-out in this list is bittergourd because it is the only vegetable that is not commonly used in cooking or consumed as a staple food in many cultures. Potato, groundnut, and carrot are all commonly used vegetables in various cuisines around the world.

The correct answer is "flower" because it is the only option that is spelled correctly. The other options, "trees," "shrubs," and "hearb," all contain spelling errors.

The given list consists of different animals, and the correct answer is "camel". The other options, yak, white fox, and mountain goat, do not match the pattern of the animals listed. Therefore, the correct answer is camel.

The correct answer is "ribbon." This is because the question is asking for a comparison to describe the thin and slender nature of the leaves of some aquatic plants. A ribbon is a long, narrow strip of material that is thin and slender in shape, making it an appropriate comparison for the leaves in question.

Animals can be categorized into herbivores, which primarily consume plants and vegetation, and carnivores, which predominantly feed on other animals. Herbivores have specialized digestive systems adapted to break down cellulose found in plants, relying on vegetation for energy and nutrients. In contrast, carnivores possess adaptations like sharp teeth and claws for hunting and consuming meat, deriving their energy from animal proteins and fats. These classifications reflect different dietary strategies among animals in the natural world.

The correct answer is butterflies because out of the given options, butterflies are the only ones that are commonly found in houses. House lizards are typically found in tropical regions but not necessarily inside houses. Earthworms are usually found in soil or gardens. Crocodiles are large aquatic reptiles and are not found in houses. Therefore, butterflies are the most appropriate answer.

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