Olympiad Test Level 1: Plants and Animals - 1 Class 4 GK MCQs & solutions

Bacteria play a crucial role in converting milk into curd through the process of fermentation. Specifically, lactic acid bacteria, such as Lactobacillus and Streptococcus, are responsible for the fermentation of milk. These bacteria consume the lactose present in milk and produce lactic acid as a byproduct. The lactic acid lowers the pH of the milk, causing it to coagulate and form curd.

Viruses, fungi, and protozoa do not have a significant role in the process of converting milk into curd.

• Arboreal animals are those that primarily live in trees.
• Monkeys, like many primates, are excellent climbers and spend a lot of their time in trees for food and safety.
• Frogs, mice, and goldfish do not primarily inhabit trees; frogs are often found near water, mice on the ground, and goldfish in aquatic environments.
• Thus, monkeys clearly fit the definition of arboreal animals.

Solution:

• Money plants use aerial roots to climb trees.
• These roots are thin and grow horizontally, allowing the plant to attach itself securely.

Solution:

• An adaptation is a feature that helps an organism survive and thrive in its environment.

• These characteristics are developed over time and increase the organism's chances of reproduction and survival.

A camel can survive for days without food and water in the desert because it stores fat in its hump. This is an example of adaptation.

• Camels store fat in their humps.
• This allows them to endure long periods without sustenance.
• Such traits are examples of adaptation to harsh environments.

Saccharomyces cerevisiae is the fungus that is commonly known as baker's yeast. The yeast cells are added to the batter of idli and dosa. The fungus performs anaerobic fermentation. The fungus utilizes the fermentable sugars and convert them to ethanol and carbon dioxide. The carbon dioxide gas causes the dough to rise and become soft and fluffy. The carbon dioxide bubbles gets trapped in the dough and when baking is done, this bubbles break and forms pores. 

Pistia is an aquatic plant which floats on water.

Solution:

Polar bears and penguins stay warm through an insulated fat layer.

• This layer acts as a barrier, trapping heat.
• It provides excellent insulation against the cold.

Coniferous trees are also referred to as evergreens.

Deciduous trees go dormant during winter weather.

• In winter, temperatures drop, leading trees to conserve energy.
• They shed leaves to reduce water loss and halt growth.
• This dormant state helps them survive until warmer months return.