the answer is definitely C
Protein structure is the three-dimensional arrangement of atoms in a protein molecule. Proteins are polymers — specifically polypeptides — formed from sequences of amino acids, the monomers of the polymer. A single amino acid monomer may also be called a residue (chemistry) indicating a repeating unit of a polymer. Proteins form by amino acids undergoing condensation reactions, in which the amino acids lose one water molecule per reaction in order to attach to one another with a peptide bond. By convention, a chain under 30 amino acids is often identified as a peptide, rather than a protein.[1] To be able to perform their biological function, proteins fold into one or more specific spatial conformations driven by a number of non-covalent interactions such as hydrogen bonding, ionic interactions, Van der Waals forces, and hydrophobic packing. To understand the functions of proteins at a molecular level, it is often necessary to determine their three-dimensional structure. This is the topic of the scientific field of structural biology, which employs techniques such as X-ray crystallography, NMR spectroscopy, and dual polarisation interferometry to determine the structure of proteins.
Protein structures range in size from tens to several thousand amino acids.[2] By physical size, proteins are classified as nanoparticles, between 1–100 nm. Very large aggregates can be formed from protein subunits. For example, many thousands of actin molecules assemble into a microfilament.
A protein may undergo reversible structural changes in performing its biological function. The alternative structures of the same protein are referred to as different conformational isomers, or simply, conformations, and transitions between them are called conformational changes.
False. I don’t know how to explain it
In plant seeds, the photoreceptor phytochrome is responsible for the process termed photomorphogenesis<span>. This occurs when a seed initially situated in an environment of complete darkness is exposed to light. A brief exposure to electromagnetic radiation, particularly that whose wavelength is within the red and far-red lights, results in the activation of the photorecepter phytochrome within the seed. This in turn sends a signal through the signal transduction pathway into the nucleus, and triggers hundreds of genes responsible for growth and development</span>
