Option A. Increases and decreases of the heart rate result from changes in the activity of the <u>medulla oblongata</u>
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What is medulla oblongata ?
- Medulla oblongata, also called medulla, the lowest part of the brain and the lowest portion of the brainstem.
- The medulla oblongata is connected by the pons to the midbrain and is continuous posteriorly with the spinal cord, with which it merges at the opening (foramen magnum) at the base of the skull.
- The medulla oblongata plays a critical role in transmitting signals between the spinal cord and the higher parts of the brain and in controlling autonomic activities, such as heartbeat and respiration
- The medulla is divided into two main parts: the ventral medulla (the frontal portion) and the dorsal medulla (the rear portion; also known as the tegmentum).
- The ventral medulla contains a pair of triangular structures called pyramids, within which lie the pyramidal tracts.
- The pyramidal tracts are made up of the corticospinal tract (running from the cerebral cortex to the spinal cord) and the corticobulbar tract (running from the motor cortex of the frontal lobe to the cranial nerves in the brainstem)
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Precipitation differences are the factor that does not contribute to "water stress" on the Earth.
<u>Explanation:</u>
- Less ocean water sources, population differences, Scarcity of economic water resources are the factor which leads to water stress on the Earth.
- Precipitation differences do not cause much difference in water stress. So it will not contribute to the water stress.
- An increase in population will cause major water stress because availability drinking water is less in the earth. Population increase can cause a major problem.
A trait that can mask another trait is known as a dominant trait.
Answer:
A pea plant that has round seeds has the genotype Rr. It is crossed with a pea plant that ... Gregor Mendel used pea plants that were heterozygous for each of two traits- seed colour and seep shape- to generate a dihybrid cross. The phenotypic ratio of the resulting offspring was nine with round and yellow seeds,