Answer:
Index fossil that is also known as indicator fossil is used to determine the age of the layers of the rocks. It says that the new layer of sedimentary rocks lie over the old layer.
The deeper we go, the older the rocks we will find. Index fossil of animals that lived or survived only for a short period of time are very useful. An example of index fossil can be Ammonites that were found in Mesozoic era that was about 25-35 million years ago.
Index fossils are used by geologists and palaeontologists to determine the relative age of rock layers and identify different geological periods. They are effective markers of time because they appear in a consistent, limited time span.
Index fossils are a powerful tool used by geologists and palaeontologists. Specifically, these fossils are used to determine the relative age of a layer of rock and identify geological periods. This is possible because index fossils are found to occur in a particular time span, and not beyond that.
For example, let's suppose a fossil of a creature that we know lived about 100 million years ago is found in a rock layer. This suggests that the rock layer would also probably be of the same period. Thus, index fossils serve as benchmarks or points of reference to determine the age of the surrounding materials.
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Answer:
cells have different shapes because they do different things
Explanation:
each cell type has has its own role to play in helping our bodies
to work properly
Answer:
during external respiration
Explanation:
Oxyhemoglobin is a type of hemoglobin carrying oxygen which is bright red in color. In the blood, it's major function is to carry oxygen molecules throughout the body.
Oxyhemoglobin is formed during external respiration. External respiration also known as breathing occurs in the lung. During external respiration, there is an exchange of oxygen and carbon-dioxide between the cells of the body and blood vessels. During breathing, oxygen diffuses into the blood, the oxygen then binds with heme in the hemoglobin found in erythrocytes to form oxyhemoglobin.
Answer:
during external respiration
Explanation:
Oxyhemoglobin is a protein formed when hemoglobin is combined with an oxygen molecule during lung respiration, also called external respiration. Its function is to transport oxygen throughout the body.
External breathing is performed when we breathe in oxygen into the body. This oxygen will be used for cells to perform cellular respiration that will be responsible for exhaling carbon dioxide out of our body.
Answer:
4. Glucose, which reduces cAMP, is an example of positive control, and lactase, which breaks down lactose, is an example of negative control.
Explanation:
During positive control, the presence of Glucose results in the repression of expression of lac operon. This concept is known as catabolite repression. During negative control, the lac genes are switched off by repressor when the inducer is absent (indicating the unavailability of lactose). But when lactose is present, lac binds the repressor protein and modifies it in order to dissociate it from the operator. The removal of the combination of repressor and inducer helps lac to be transcribed and expressed.
radiative energy is energy in light. Sunlight carries this form of energy, as do other forms of light including X-rays and radio waves.
Answer:
It is the bell sign, this can be positive due to nerve involvement or due to an ideopathic question.
The bell sign is positive or negative according to different signs perceived by the dental professional or maxillofacial surgeon.
It is the affection of the seventh cranial nerve, that is to say, of the facial nerve.
Explanation:
The facial nerve is a nerve that is responsible for the sensitivity of the face and the motor skills of the muscles of mime, chewing, swallowing and facial expressions.
The pathognomonic signs are:
facial pain, hyperacusis, decreased ocular tearing, diagusia, and when the patient tries to close the eye it deviates upwards and to the side.
In addition to these signs there is a very characteristic one that is anesthesia or hemifacial paralysis, that is, of the middle of the face.
The positive bell sign usually occurs in patients who have serious automobile accidents.