Give scientific reason: Life is not possible without protein.

(N/A) $\Rightarrow$ Proteins present in the plasma membrane transport materials across it.
$\Rightarrow$ Immunoglobulin proteins provide immunity against harmful pathogens.
$\Rightarrow$ Some proteins act as structural components of hormones.
$\Rightarrow$ Proteins are indispensable components of enzymes,which catalyze metabolic reactions.
$\Rightarrow$ Collagen is the most abundant protein in the animal world,providing structural support.
$\Rightarrow$ Ribulose bisphosphate carboxylase-oxygenase $(RuBisCo)$ is the most abundant protein in the whole biosphere,essential for carbon fixation.
$\Rightarrow$ Proteins are essential for various physiological processes,such as transport (e.g.,hemoglobin for respiratory gases).
$\Rightarrow$ Thus,life is not possible without proteins as they are the building blocks and functional machinery of cells.