Page 197 - Innovator's Science-8

in Earth’s orbit or volcanic erup ons—the current rapid warming is driven by humans burning fossil fuels.
This releases large amounts of greenhouse gases like carbon dioxide and methane, which trap more heat
in the atmosphere, intensifying the natural greenhouse effect. As a result, we see faster warming, mel ng
ice caps, rising sea levels, and more extreme weather events. This human influence, combined with issues
like biodiversity loss and pollu on, creates a triple planetary crisis that threatens life on Earth. Unlike
slower natural changes in the past, the current warming is happening quickly and requires urgent ac ons,
such as switching to renewable energy, to protect ecosystems and maintain Earth’s balance.
8. If there were no atmosphere on the Earth, would it affect life, temperature, and water on the planet?
Explain.
Ans. Without an atmosphere:
• Life: Life would struggle to survive, as most organisms require oxygen for respira on. The absence of
the ozone layer would allow harmful UV rays to damage cells, affec ng plants, animals, and humans.
• Temperature: Earth would lose heat to space without the greenhouse effect, becoming extremely
cold, similar to the Moon. Day me temperatures could soar due to unfiltered sunlight, and nights
would be freezing.
• Water: Liquid water would evaporate or freeze due to extreme temperature swings and low pressure,
making it unavailable for life processes. The water cycle (rainfall, clouds) would cease without
atmospheric water vapour.

9. Discuss five examples of vegeta ve propaga on.
Ans. Vegeta ve propaga on is a way plants reproduce without seeds. Instead of using seeds, new plants
grow from parts of the parent plant like stems, roots, or leaves. This means the new plants are exactly
the same as the parent. The five examples are:
• Money Plant: A stem cu ng with a node grows roots when placed in water or soil, forming a new
plant.
• Potato: The “eyes” (buds) on a sprouted potato can be planted to grow a new potato plant.
• Ginger: A piece of ginger rhizome with a bud, when planted in soil, develops into a new plant.
• Sugarcane: Stem cu ngs with nodes are planted to produce new sugarcane plants, as sugarcane
rarely produces seeds.
• Bamboo: Sec ons of bamboo stems or rhizomes can be planted to grow new bamboo plants, relying
on vegeta ve propaga on.

Put on your Problem Solving Skills
Thinking cap OMR Sheet

A. Darken the correct options in the OMR Sheet:

1. Which reproduction type involves only one parent?
a. Sexual b. Budding
Wrong Methods
c. Pollination d. Fertilisation
2. Which planet has a very high surface temperature due to greenhouse Correct Method

gases?
a. Mercury b. Mars 1. a b c d
c. Venus d. Jupiter 2. a b c d

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