Decomposer hope this helps
Answer:
The concentration gradient is the driving force.
Explanation:
Passive transport of substance occurs when they are moved from the region of their higher concentration to that of their lower concentration. The concentration gradient is the difference in the concentration of substances between two regions or across the membrane. The concentration gradient of substances drives their passive movement. The passive movement of substances does not use metabolic energy. Simple diffusion and facilitated diffusion are two examples of this transport.
The correct example about the relationship between the insect hormones ecdysteroid and PTTH is interaction of the endocrine and nervous system. Hence, Option A is correct.
ENDOCRINE SYSTEM:
It is a complex system which is under hormonal control. Hormones are released by the glands and it cordinates body functions from metabolism to growth and development.
NERVOUS SYSTEM:
It is a complex system consisting of organised group of cells called neurons that carry messages from brain and spinal cord to other various body parts.
As PTTH (prothoracicotropic hormone) stimulates prothoracic gland of an insect that triggers the release of ecdysone hormone for the stimulation there should be an neuroendocrine mechanism. Thus, Option A is correct.
Learn more about hormonal interations here:
brainly.com/question/1218436
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