Answer: B) are excited by light that falls in the center of their receptive field.
Explanation:
There are two types of bipolar cells present in the retina which are differentiated on the way the centres of their receptive fields respond to light. The names of bipolar cells are ON-centre and OFF-centre.
If a light fall at the centre of the receptive field of a bipolar cell, it will experience an exciting effect on that cell, resulting in it being depolarized, it is an ON-center cell.
Hence, the correct option is B.
Answer:
All options are correct
Explanation:
Fossils are the remains of organisms (animals and plants) preserved in a rock. Scientists (geologists & palaebiologists) have used fossils to study the diversity of organisms in the past. This is based on their preserved morphological features. For example, several species of foraminifera has been identified in the rocks. Among them, some species are present today whereas others have become extinct.
Similarly, fossils are the indicators of past climate (e.g. temperature) as well. This means, if a specific species can survive at a particular temperature, its presence suggest that particular environment. For example, corals survive in tropical waters at specific depth and sunlight. So, if we find corals fossils, the cliamte of that particular age would be roughly the similar.
In the end, fossils can also provide evidence of orogeny (mountain building) process. These are typically plants fossils which cannot move and their remains are preserved in the folding rocks.
Answer:
Angiotensin II is a potein VASOCONSTRICTOR that helps regulate blood pressure. Angiotensinogen, is an inactive hormone synthesized and released continuously from the LIVER. Its activation, which occurs within the BLOOD, is initiated by the enzyme renin. Renin is released from the juxtaglomerular apparatus of the KIDNEYS in response to either (1) LOW blood pressure (as detected by decreased stretch of BARORECEPTORS within granular cells, or by decreased NaCl detected by CHEMORECEPTORS within macula densa cells); or (2) stimulation by the SYMPATHETIC division. The sequential action of renin and angiotensin converting enzyme (ACE) causes the formation of angiotensin II (the active form of the hormone).
Explanation:
Angiotensin is a peptide hormones that regulate blood pressure by causing increase in blood pressure through vasoconstriction. It is a part of the renin- angiotensin system that regulate the internal pressure of the blood. It is stimulated when the level of blood pressure reduces or there is an decrease in the sodium chloride in the blood. It effects is to vasoconstrict the blood vessels thereby increasing the blood pressure in the vessels. Angiotensinogen is the inactive hormone synthesized by the liver and upon activation through baroreceptors or chemoreceptors, the liver releases angiotensinogen into the blood stream to be ctivated by the enzyme secreted from the kidney's juxtaglumerular apparatusand then activated to teh angiotensinogen I, angiotensinoI is then activated into angiotensin II by the angiotensin II by the angiotensin converting enzyme. Angiotensin also causes the increase in the aldosterone secretion from the adrenal cortex to promote the retention of sodium by the kidneys, this also helps to increaee the blood pressure. Various receptors helps in signalling the body to a reduced blood pressure level. This includes the baroreceptors which are pressure receptors and detect changes in pressure of the blood; chemorecptors which are chemical receptors that detect the change in the concentration of sodium and chloride ion in the blood. All this function together with the sympathetic division of the CNS to help the body regulates its change in blood pressure in a given time.
I think c is the correct answer
