What is the classification of livingthings called?A biology(B astrologyc) taxonomyD astronomy

The coelacanth is another lobe-finned fish that is a living fossil. It is thought to have evolved into roughly its current form about 408 million years ago, during the early Devonian, and has not essentially evolved further from its ancient form.

What is fossil index?

A fossil index is a paleontological or archaeological remain whose presence can be used to date with some precision the stratigraphic unit in which it is found because they are particular or exclusive of a certain period of geological history, or of Prehistory, or indicators of a certain paleoenvironment.

In general, the taxa or cultural modes of the past that gave rise to the guide fossils had a very short duration on a geological -or historical- scale, which means that their presence is limited to chronological -or cultural- coordinates, in the case of prehistoric cultures-, very limited. That is, if a guide fossil appears in a stratum, that stratum can be dated with enough accuracy.

Therefore, The coelacanth is another lobe-finned fish that is a living fossil. It is thought to have evolved into roughly its current form about 408 million years ago, during the early Devonian, and has not essentially evolved further from its ancient form.

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The coelacanth is another lobe-finned fish that is a living fossil. It is thought to have evolved into roughly its current form about 408 million years ago, during the early Devonian, and has not essentially evolved further from its ancient form.

Mitosis is simply described as having four stages—prophase, metaphase, anaphase, and telophase; the steps follow one another without interruption. The entire four-stage division process averages about one hour in duration, and the period between cell divisions, called interphase or interkinesis, varies greatly but is considerably longer.

During interphase the chromosomes are dispersed in the nucleus and appear as a network of long, thin threads or filaments, called the chromatin. At some point before prophase begins, the chromosomes replicate themselves to form pairs of identical sister chromosomes, or chromatids; the deoxyribose nucleic acid (DNA) of the chromosomes is synthesized only during interphase, not while mitosis is in process.

During prophase the two chromatids remain attached to one another at a region called the centromere, but each contracts into a compact tightly coiled body; the nucleolus and, in most cases, the nuclear envelope break down and disappear. Also during prophase the spindle begins to form. In animal cells the centrioles separate and move apart, and radiating bundles of fibers, called asters, appear around them. Some sets of fiber run from one centriole to the other; these are the spindle fibers. In plant cells the spindle forms without centrioles.

During metaphase the chromosomes congregate at a plane midway between the two ends to which the spindle tapers. This is called the equatorial plane and marks the point where the whole cell will divide when nuclear division is completed; the ends of the spindle are the poles to which the chromatids will migrate. The chromatids are attached to the spindle fibers at the centromeres.

During anaphase the two chromatids of each chromosome separate and move to opposite poles, as if pulled along the spindle fibers by the centromeres. During telophase new nuclear envelopes form around the two groups of daughter chromosomes (as they are now called), the new nucleoli begin to appear, and eventually, as the formation of the two daughter nuclei is completed, the spindle fibers disappear. The chromosomes uncoil to assume their dispersed distribution within the interphased nucleus. Cytokinesis, which may begin before or after mitosis is completed, finally separates the daughter nuclei into two new individual daughter cells.

A considerable variance in the degree and timing of these stages exists across species, and cells can be classified by their mitotic characteristics. Despite the relative ease of observation of the physical stages of mitosis under the microscope (primarily because the chromosomes stain readily when in their coiled state), the exact chemical and kinetic nature of mitosis is not yet fully understood. For instance, the spindle has been determined to consist largely of thin, elongate tubules called microtubules, but their functions have yet to be understood.

During the second trimester of a woman's pregnancy, the mother starts feeling the fetus's movements for the first time and the fetus's hands and feet start to appear. Therefore, the correct statements are option A and option C.

What is the second trimester?

The second trimester period ranges from 13 weeks to 27 weeks and is considered to be the middle stage of pregnancy. During this period, significant growth and development can be seen in the developing fetus, and some organs get fully developed.

During the second trimester, any health issues associated with the fetus can also be detected. The second trimester is a very important stage of pregnancy where the mother and her fetus both experiences a significant change.

During the second trimester of pregnancy, the fetus's hands and feet begin to appear. However, the mother also starts feeling the movements of the fetus usually during the second trimester. However, the teeth fully form after birth.

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Answer:

a. the mother feels the fetus move for the first time

Explanation: