The two structures that could be found only in plant cells are chloroplast and the cell wall. As these two structures are not present in the animal cells, therefore the chloroplast and cell wall are the two positive identifications of a plant cell under the microscope.
Ostrich is the biggest of all birds
Facilitated diffusion is a particular type of simple diffusion process that does not require energy intake for relatively small and larger molecules and compounds to diffuse, as the direction of diffusion is from high to low concentrations.
The correct answer is protein.
Proteins are macromolecules composed of amino acids with the wide range of structures. Protein functions are diverse:
• structural proteins-maintaining the cell shape, (for example, proteins are structural elements in connective tissues like cartilage and bone in vertebrates),
• Enzymes - catalyze the biochemical reactions in cells-.
• Monitors- changing their activity in response to metabolic signals
• Part of the extracellular matrix or involved in intercellular communication…