Blood flows to the brain through the internal carotid and vertebral arteries and away from the brain through the internal jugular vein. The internal carotid artery supplies the brain, while the external carotid nourishes other portions of the head, such as the face, skull, scalp and the meninges. The vertebral arteries provide supply to the upper spinal cord, brainstem, cerebellum, and the posterior part of the brain.
Answer:
The answer to this definition is: ACTION POTENTIAL
Explanation:
Action potential is a phenomenon in nervous system used to describe a change in electrical current that occurs when an impulse passes through a neuron or nerve cell. Action potential is induced when sodium (Na+) ions move from the extracellular environment into the intracellular environment.
Impulse travels across the axon of a neuron and thereby causes a difference in the electric potential i.e. - mv to + mv. This process, according to this question, whereby a change in electrical potential occurs due to the passage of an impulse through a nerve cell is termed ACTION POTENTIAL.
<span>b. photosynthetic organisms provide energy for other organisms on earth.
B is the most suitable answer as photosynthetic organisms get their energy from the sun, and other organisms get their energy from photosynthetic organisms, so the sun is the source of energy for all life.</span>
MEIOSIS
This is a process by which a cell divides twice producing 4 cells. These cells contains half of the original genetic material. Sex cells usually undergo these process. During meiosis 1 a cell divides twice producing four daughter cells. There 5 phases in meiosis 1 which are Interphase, Prophase, Metaphase, Anaphase, Telophase and cytokinesis.The second time the cell divides is called meiosis II. These also have phases as the meiosis I but cellular changes is different.
<span>The complex organic molecules are broken down by them to get energy. </span>
<span>The individual components of these compex molecules are SET FREE in the environment ( air, soil , water ). </span>
<span>Thus these are now FREE for recycling . </span>
<span>example - A protein molecule is a very compex and big one with C,H,O, AND N in addition it may contain other atoms such a Fe , S as well ! It has some energy stored in it . </span>
<span>When it is decomposed , all the individual elements mentioned above in capital letters are released for recycling . </span>
<span>This is equally true for a dead tree .</span>
