The correct answer is the organ.
The multicellular species are formed of various parts, which are required for survival. These parts are differentiated into the levels of the organization. There are five different levels, which are named as cells, tissue, organs, organ systems, and organisms.
When two or more layers of tissue function together, they produce an organ. All the animals comprise vital organs, without which they cannot survive. These include the kidneys, liver, lungs, brain, and heart.
Answer:
A <u><em>receptor</em></u> is a protein that recognizes and responds to a signal.
Explanation:
A receptor is a protein molecule present on the cells on which the signalling molecules can bind and generate a physiological response. Some receptor molecules can also respond to Sun and light. Each type of cell has specific receptors molecules and hence can respond to specific signals. The receptor molecules hence tend to receive signals for a cell. Molecules such as hormones bind to the receptors.
Solution:
According to the accepted current theory, known as the fluid mosaic model, the plasma membrane is composed of a double layer (bilayer) of lipids, oily substances found in all cells. The fluid mosaic model was first proposed by S.J. The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character. Plasma membranes range from 5 to 10 nm in thickness.
Thus this is the required answer.
Facilitated diffusion occurs in the cell body. It is the process of transporting particles into and out of a cell membrane. Energy is not required because the particles move along the concentration gradient. Permeable means that particles, ions, or water can cross the membrane. Hope I’ve helped ;)
