<span>a. spinal cord
Spinal Cord is the part of the nervous system responsible for connecting the brain to the body.
</span>The nervous system is divided into two groups. The Central Nervous System and the Peripheral Nervous System.
The Central Nervous System involves the Brain and the Spinal Cord. Its contains the integrative and control centers.
<span>The Peripheral Nervous System involves the cranial nerves and spinal nerves. It is composed of the communication lines between the Central Nervous System and the rest of the body.</span>
Biologists recognize five levels of cell organization. The lowest and simplest is the cellular level. Organisms here are either unicellular organisms, like protozoa, or colonial organisms. Colonial organisms are composed of single-celled individuals that stay together to sustain the life of the whole colony. Next on the scale of complexity is the level occupied by tissue. A tissue is a group of similar cells that perform a similar activity. Tissues that are organized around a common function together make up an organ, the third level of complexity. The fourth level of organization is the system, formed by a group of organs that together perform a specific bodily process. The fifth and highest level is the organism level, in which body systems work together in a structure capable of independent life.
The Drilling sample of the Seafloor spreading theory helped in determining rock ages on the floor of ocean.
Explanation:
The formation of crusts of ocean by the process of volcanic eruptions in the ridges of the middle ocean is the theory of seafloor spreading proposed by Hammond Hess. The movement of tectonic plates continuously forms sea floors through spreading of seafloor. The several evidences in support of this theory has been seen, of which some are – molten material eruptions, magnetic stripes in rocks and rock ages.
The drilling evidence is the final one that was proved by taking samples of rock by drilling in ocean and by bringing them with pipes. The observation of these rocks proved that older rocks were collected from farther ridges and youngers are found in the central ridges.
Answer:
The marine clamworm, Nereis, is carnivorous therefore its digestive system differs from that of the herbivorous earthworm, Lumbricus. The mouth and jaws are retractable (Figure 8, 9). If the jaws are retracted, cut along the midline of the pharynx and pull the jaws out with a pair of forceps.
Explanation:
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