The structure that prevents the collapse of the trachea during breathing is: MCQ with Answer and Explanation

Explanation:
Pinocytosis (cell drinking) is a type of endocytosis where the cell membrane forms small vesicles to engulf extracellular fluid and dissolved substances. Phagocytosis is for large particles, exocytosis is export, endocytosis is general term.

Explanation:
The central nervous system comprises the brain and spinal cord, protected by the bony cranium and vertebral column, respectively, along with meninges. Neurons are highly excitable cells capable of generating and conducting action potentials in response to stimuli. Therefore, statements 1 and 2 are correct, while statement 3 is fundamentally incorrect.

Explanation:
The chemical evolution theory, also known as the biochemical theory of the origin of life, was proposed independently by Alexander Oparin (1924) and J.B.S. Haldane (1929). They proposed that life originated from pre-existing non-living organic molecules (like RNA, proteins, lipids) through a series of complex chemical reactions in the primitive reducing atmosphere of Earth.