Answer:
Stimulus in biology can be defined as an obvious change in either the chemical or physical structure of an organism' environment (either external or internal).
Explanation:
Stimulus in biology can be defined as an obvious change in either the chemical or physical structure of an organism' environment (either external or internal). Thus, all living organisms (both animals and plants) respond to changes in their environment and consequently, an appropriate response or reaction is made. Also, stimulus arising from within the organism is known as internal stimulus while those from its environment are known as the external stimulus.
In organisms, the specialized cells that detect stimulus are generally known as sensory receptors while a group of these receptors is referred to as sense organ. Therefore, the senses are necessary for behavior because stimuli must be sensed in order to respond.
Stimulus control can be defined as a phenomenon that arises when a living organism responds or behaves in the presence of a stimulus and in another way in the absence of a stimulus.
<em>For example, opening the door of a microwave oven as soon as its timer beeps.</em>
<em>Example II; When your body touches a hot object, you quickly move away and feel some pain subsequently. </em>
Answer:
Explanation:
Superior/Inferior Vena cava-----------Right Atrium ---------Tricuspid valve ------right ventricle -------pulmonary semi-lunar valve------pulmonary trunk-----------pulmonary arteries --------lung capillaries -------- pulmonary veins --------left atrium -------mitral valve --------left ventricle ------- aortic semi-lunar valve -------aorta --------- tissues of body ------------superior and inferior vena cava.
Sarah is the infected while <span>Streptococcus pneumonia is the virus?</span>
Answer:
Harmful mutations may cause genetic disorders or cancer. A genetic disorder is a disease caused by a mutation in one or a few genes. A human example is cystic fibrosis. A mutation in a single gene causes the body to produce thick, sticky mucus that clogs the lungs and blocks ducts in digestive organs.
Mutations arise spontaneously at low frequency owing to the chemical instability of purine and pyrimidine bases and to errors during DNA replication. Natural exposure of an organism to certain environmental factors, such as ultraviolet light and chemical carcinogens (e.g., aflatoxin B1), also can cause mutations.
only a small percentage of mutations cause genetic disorders—most have no impact on health or development. For example, some mutations alter a gene's DNA sequence but do not change the function of the protein made by the gene.
