Darwin's theory of evolution is primarily based on the concept of: MCQ with Answer and Explanation

Explanation:
In both mitochondria and chloroplasts, ATP synthase uses the energy stored in a proton gradient across a membrane (thylakoid membrane in chloroplasts, inner mitochondrial membrane) to drive the synthesis of ATP from ADP and Pi. This process is chemiosmosis, proposed by Peter Mitchell.

Explanation:
The cell membrane (plasma membrane) is selectively permeable, meaning it allows certain substances to pass through while restricting others, maintaining cellular homeostasis. The nucleus is the control center of the eukaryotic cell, housing the DNA and directing cellular activities like growth, metabolism, and reproduction. The cell wall is a rigid outer layer present in plant cells, fungi, and bacteria, but it is completely absent in animal cells, which only have a flexible cell membrane. Thus, statements 1 and 3 are correct.

Explanation:
Homologous organs share a common ancestral origin and structural plan but may have different functions (e.g., human arm, whale flipper, bat wing). This indicates divergent evolution. Analogous organs have different origins but similar functions (e.g., wings of birds and insects) due to convergent evolution. Vestigial organs are reduced and non-functional, like the human appendix.