Louis Pasteur is famous for developing the first vaccine for: MCQ with Answer and Explanation

Explanation:
Thrombin converts soluble fibrinogen into insoluble fibrin monomers, which polymerize and cross-link to form a stable blood clot. Fibrinogen is the precursor, prothrombin is the precursor of thrombin. The clotting cascade amplifies the signal.

Explanation:
A food chain is a linear, simplified sequence showing the transfer of energy and matter from one organism to another through consumption. A food web is a more realistic, complex network of interconnected food chains, illustrating the multiple feeding relationships and pathways of energy flow in an ecosystem. While nutrients (matter) are continuously recycled in an ecosystem through biogeochemical cycles, energy flows unidirectionally and is eventually lost as heat; it is not recycled. Thus, statements 1 and 2 are correct.

Explanation:
Chloroplasts are the sites of photosynthesis in plant cells, converting solar energy into chemical energy (food). Hence they are called the kitchen of the cell. Mitochondria are the powerhouse, generating ATP; ribosomes are protein factories; Golgi apparatus is the packaging center.