The answer is skin
The first line of defence is your innate immune system. Level one of this system consists of physical barriers like your skin and the mucosal lining in your respiratory tract. The tears, sweat, saliva and mucous produced by the skin and mucosal lining are part of that physical barrier, too.
Answer:
The chemical receptors of cells have been defined as molecular structures to which other molecules considered as chemical messengers (neurotransmitters, hormones and other neuroactive molecules) specifically bind.
Chemical receptors can be located on the plasma membrane into which they insert by crossing it. Membrane domains have been defined for them and also on both sides of the membrane. The one on the external side corresponds to the binding site for messengers that come from other cells, a situation that defines the so-called heteroreceptors. If messengers coming from the cell itself join that site, the so-called autoreceptors are defined.
But chemical receptors can also be located inside cells. They are intracellular receptors and are found in the cytoplasm or in the nucleus. Messages act on them, which due to their chemical nature can cross the plasma membrane, such as steroidal hormones, thyroid hormones and neurosteroids
Explanation:
I hope my answer helped you
Lift by yourself. you shouldn’t do this if there aren’t anything possibly else to do, Like last option, any other resources around, arent. but if the patient is physically able to walk , that’s okay too .
Explanation:
b because exercising during ilnesses is not healthy
