Explanation

Science is typically divided into four main categories:

1. Natural Sciences: Focus on the physical world and its phenomena.
2. Formal Sciences: Concerned with abstract systems and logical reasoning.
3. Social Sciences: Explore human behavior and societal structures.
4. Applied Sciences: Use scientific principles to solve practical problems and develop technology.

Explanation

• Venera-9 was the first spacecraft to land on the surface of Venus.
• Launched by the Soviet Union in 1975.
• It was designed to study the Venusian atmosphere and surface.
• It successfully transmitted data from the planet's surface for 53 minutes before its batteries failed.

Explanation

• The optical centre is the point within a lens where a ray of light passes through without changing its direction or path.
• This point is located at the centre of the lens, on the optical axis.

Explanation

• The pressure exerted by a liquid at a given point increases with the depth of the liquid, as the weight of the liquid above increases.
• This is described by Pascal's Law, which states that the pressure at a point in a fluid is proportional to the depth of the fluid.

Explanation

• Filtration is a process that removes suspended sand particles and insoluble physical impurities from water.
• By passing it through a filter medium, such as sand, gravel, or a membrane.

Explanation

• Flowers are the reproductive structures of plants, and they produce seeds through sexual reproduction.
• This process involves the fusion of male and female gametes (pollen and ovules) to form a zygote, which develops into a seed.

Explanation

Microorganisms are typically classified into three main groups:

1. Bacteria (single-celled prokaryotes)
2. Viruses (tiny infectious agents that replicate inside the cells of an organism)
3. Fungi (organisms that obtain their nutrients by decomposing organic matter or by forming symbiotic relationships with other organisms)

Explanation

• Amphibians are a group of cold-blooded animals that live in both aquatic (water) and terrestrial environments (land).
• They have moist, smooth skin that helps them to breathe and regulate their body temperature.
• Examples: frogs, toads, salamanders, and newts.

Explanation

• Omnivores can be both secondary and tertiary consumers, depending on their diet and position in the food chain.
• They can eat primary consumers (herbivores) as secondary consumers, and also eat secondary consumers (other carnivores or omnivores) as tertiary consumers.

Explanation

• Tertiary consumers are animals that eat primary and secondary consumers.
• They are typically apex predators that have no natural predators in the wild and are at the top of their food chain.
• Examples of tertiary consumers include lions, sharks, bears, and humans.