Answer:
antigens
Explanation:
Specific immune responses are triggered by antigens. Antigens are usually found on the surface of pathogens and are unique to that particular pathogen. The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies.
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:
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Answer:
Animals are multi-cellular organisms composed of eukaryotic cells, while bacteria are single-cell prokaryotic organisms. Animal cells are larger in size compared to bacteria cells. Animal cells don't have cell walls but bacteria cells have well defined walls.
Explanation:
Answer:
This is because ladybugs are replaced by pesticides that are responsible for not only contaminating crops but also for releasing dangerous gases into the ozone layer. Therefore, the use of these insects in crops makes the air more pure or avoids contaminating it with life-threatening pesticides for many living organisms.
The microbial theory of disease or germ theory of infectious diseases is a scientific theory that proposes that microorganisms are the cause of a wide range of diseases. These tiny organisms, almost all too small to see with the naked eye, invade humans, animals, and other hosts. Its growth and reproduction within the carrier can cause disease. "Germ" or microbe can refer to a virus, bacteria, protist, fungus, or prion.
Explanation:
The theory was a scientific discovery made in the second half of the 19th century, demonstrated by Louis Pasteur and that replaced previous explanations for the disease, such as the miasmatic theory or the theory of humors. Although highly controversial when proposed, it is now central to modern medicine and clinical microbiology, leading to such important innovations as the development of the vaccine, antibiotic, sterilization, and hygiene as effective methods against the spread of contagious diseases.