It's some change in the conditions around the organism, which the organism can detect and respond to. A change in temperature, more light, or something physically poking the organism are examples.
C seems like the correct answer
Hypothalamus; pituitary gland
Hypothalamix-pituitary-adrenal axis is a complex set of direct influences and feedback interactions among the three organ components which are the hypothamus, pituitary gland and adrenal gland. These organ and their interactions forms the HPA axis that controls the reaction to stress and regulates many body processes,including digestion, immune system mood and emotions
<h2>Order of parts of a microscope
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First – ocular lens
Second – Body tube
Third – Revolving Nosepiece
Fourth – Objective lens
Fifth – Coverslip
Explanation:
Ocular lens: The lens present in the eyepiece at the top of the microscope, close to the eyes, through which a person looks through the microscope to view the specimen. Magnification of ocular lens in a compound microscope is usually 10x
Body tube: The tube that connects the eyepiece with the objective of the microscope for continuous optical alignment.
Revolving Nosepiece: The turret that holds the objective and revolves to select the objective lens according to its magnification
Objective lens: The objective lens is located above the specimen rack. Objective lens creates the primary image of the specimen viewed through the eyepiece. A single compound microscope can have more than two objective lens and their magnification ranges from 4x, 10x, 40x, 100x power.
Coverslip: The cover glass which covers the objective lens and prevent from touching the specimen
. This is the object directly above the specimen.