Taxnomy categories: It is also called Linnaean hierarchy or taxononmic hierarchy or Taxonomic classification. It was first proposed by Linaeus. Hierarchy of categories is the classification of organism in a definite sequence of categories (taxonomic categories) in a descending order starting from kingdom.

The number of similar characters of categories decreases from lowest rank to highest rank. The hierarchy includes seven obligate categories – kingdom, division or phylum, class, order, family, genus and species. The categories are arranged in descending sequence keeping the kingdom at the top.

In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in a taxonomic hierarchy.

Blinking of eyes is  needed to clear away dust particles and spread lubricating fluids across the eyeball. Every time you blink, your eyelids spread a cocktail of oils and mucous secretions across the surface of the eye to keep your globes from drying out. Blinking also keeps eyes safe from potentially damaging stimuli, such as bright lights and foreign bodies like dust. The very act of blinking suppresses activity in several areas of the brain responsible for detecting environmental changes, so that you experience the world as continuous.

Vomiting is believed to be controlled by two distinct brain centres, the vomiting centre and the chemoreceptor trigger zone ,both located in the medulla oblongata. The vomiting centre initiates and controls the act of emesis, which involves a series of contractions of the smooth muscles lining the digestive tract.

These contractions begin at the small intestine and move successively through the stomach and the esophagus until the stomach contents are forced out the mouth. The vomiting centre responds directly to stimuli from various parts of the body that may be stressed or diseased. The chemoreceptor trigger zone, by contrast, is stimulated by many toxins and drugs. Activation of this brain region stimulates the vomiting centre, which initiates emesis in an effort to rid the body of the toxin.

Golgi apparatus(Golgi complex or Golgi body):It is membrane-bound organelle of eukaryotic cells (cells with clearly defined nuclei) that is made up of a series of flattened, stacked pouches called cisternae.

The Golgi apparatus is responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations.

It is located in the cytoplasm next to the endoplasmic reticulum and near the cell nucleus. While many types of cells contain only one or several Golgi apparatus, plant cells can contain hundreds.

1. Cell Division:-
Mitosis: A somatic cell divides once. Cytokinesis (the division of the cytoplasm) occurs at the end of telophase.
Meiosis: A reproductive cell divides twice. Cytokinesis happens at the end of telophase I and telophase II.

2. Daughter Cell Number:-
Mitosis: Two daughter cells are produced. Each cell is diploid containing the same number of chromosomes. Meiosis: Four daughter cells are produced. Each cell is haploid containing one-half the number of chromosomes as the original cell.

3. Genetic Composition:-
Mitosis: The resulting daughter cells in mitosis are genetic clones (they are genetically identical). No recombination or crossing over occur.
Meiosis: The resulting daughter cells contain different combinations of genes. Genetic recombination occurs as a result of the random segregation of homologous chromosomes into different cells and by the process of crossing over (transfer of genes between homologous chromosomes).

4. Length of Prophase:-
Mitosis: During the first mitotic stage, known as prophase, chromatin condenses into discrete chromosomes, the nuclear envelope breaks down, and spindle fibers form at opposite poles of the cell. A cell spends less time in prophase of mitosis than a cell in prophase I of meiosis.
Meiosis: Prophase I consists of five stages and lasts longer than prophase of mitosis. The five stages of meiotic prophase I are leptotene, zygotene, pachytene, diplotene, and diakinesis. These five stages do not occur in mitosis. Genetic recombination and crossing over take place during prophase I.

5. Tetrad Formation:-
Mitosis: Tetrad formation does not occur.
Meiosis: In prophase I, pairs of homologous chromosomes line up closely together forming what is called a tetrad. A tetrad consists of four chromatids (two sets of sister chromatids).

6. Chromosome Alignment in Metaphase:-
Mitosis: Sister chromatids (duplicated chromosome comprised of two identical chromosomes connected at the centromere region) align at the metaphase plate (a plane that is equally distant from the two cell poles). Meiosis: Tetrads (homologous chromosome pairs) align at the metaphase plate in metaphase I.

7. Chromosome Separation:-
Mitosis: During anaphase, sister chromatids separate and begin migrating centromere first toward opposite poles of the cell. A separated sister chromatid becomes known as daughter chromosome and is considered a full chromosome.
Meiosis: Homologous chromosomes migrate toward opposite poles of the cell during anaphase I. Sister chromatids do not separate in anaphase I.