Explanation

 In the human body, there are 3 pairs of false ribs on each side, corresponding to the 8th, 9th, and 10th pairs of ribs.

These ribs do not directly connect to the sternum (breastbone) like the true ribs (pairs 1-7).

Instead, their cartilage connects to the cartilage of the 7th rib, which is a true rib. 

Explanation

Soil pollution can be caused by various factors including acid rain, ozone, and aerosols.

Explanation

Alkali metals (such as lithium, sodium, potassium, etc.) act as reducing agents.

They readily lose their single valence electron to form positive ions, which means they donate electrons in reactions

Explanation

The notochord is a flexible, rod-shaped structure that is present during the embryonic stage of all chordates

It provides support and defines the primitive axis of the body.

This characteristic is a key feature that distinguishes chordates from non-chordates.

Explanation

Kangaroos belong to the infraclass Metatheria, which includes all marsupials.

Metatherians are mammals that give birth to relatively undeveloped young

they are mostly found in Australia and the Americas.

Explanation

Mitosis is a type of cell division that results in two daughter cells, each with the same number of chromosomes as the parent cell, producing somatic cells (body cells).

It is responsible for:

• growth
• repair
• asexual reproduction in organisms.
  

Explanation

Calcitonin is produced and secreted by the parafollicular cells (or C cells) of the thyroid gland

Its primary function is to lower blood calcium levels by inhibiting osteoclast activity in bones, which reduces bone resorption, and by increasing calcium excretion in the kidneys.

This action helps to maintain calcium homeostasis in the body.

Explanation

Ice always floats because it is less dense than regular water.

Because frozen water molecules form a crystal

They take up more space and have a lower density than regular liquid water.

Explanation

The fungal bodies are formed by long, slender, thread-like structures called hyphae.

A collection of hyphae is known as mycelium.

Hyphae are of two types based on the presence or absence of a septum:

• septate
• Aseptate hyphae
  

Explanation