(i) Long nails can cause diseases to us. Because, the microbes present in the dirt deposited under the long nails go inside our body while we are eating and can cause diseases.
(ii) We should properly cut our nails regularly, as nails keep on growing.
(iii) (a) I will keep an eye on the nails of my youngers, friends and relatives and persuade to cut nails regularly to those who keep long nails than desired.
(b) I along with my friends, teachers and NGOs organise lectures and discussions, especially in nearby rural areas, to educate people in this regard.

Mitochondria are known as 'Power House' of the cell. They are said so because the energy required for various life activities is released by mitochondria in the form of ATP molecules. The body uses energy stored in ATP for synthesis of new compounds and for mechanical work. As ATP instantly provide energy, the are called energy currency of the cell?

(a) Plant cells have big vacuoles full of cell sap that provide them turgidity and rigidity. Plant vacuoles store amino acids, sugars, various organic acids and some proteins.
(b) In unicellular organisms, they may serve the following purposes:
(i) Forming Food Vacuoles: In single-celled organisms like Amoeba, the food vacuole contains the food items that the Amoeba has ingested. The food items are digested by the enzymes later on.
(ii) Removal of excess water and wastes: In some unicellular organisms, specialised vacuoles play important roles in expelling excess water and some wastes from the cell.

These are membrane-bound vesicles which bud off from Golgi apparatus. They contain powerful enzymes capable of digesting or breaking down all organic material. The enzymes present in lysosome are synthesised on RER. The membrane that bound lysosomes does not allow the enclosed enzymes to pass freely into the cell cytoplasm. Thus, protects the cell from autolysis (self-dissolution or breakdown). They are absent in RBCs and a few plant cells, for example, yeast, fungi and green algae.

Endoplasmic reticulum helps in the transport of substances between various regions of the cytoplasm or between the cytoplasm and the nucleus. Endoplasmic reticulum also functions as a cytoplasmic framework providing a surface for some of the biochemical activities of the cell. In vertebrates, SER present in the liver cells also plays an important role in detoxifying poisons and drugs.

The part of protoplasm which remains after excluding nucleus is known as cytoplasm. Cytoplasm contains aggregate molecules of various chemicals and cell organelles. Most of the biochemical reactions such as protein synthesis, release of energy etc. take place in cytoplasm or organelles present in the cytoplasm.

Prokaryotic Cell:
Nuclear region is poorly defined due to absence of a nuclear membrane and is known as nucleoid.
Eukaryotic Cell:
Membrane-bound cell organelles are present.

It performs the following functions in the plant cell:
(i) It gives a definite shape to the cell.
(ii) It provides rigidity and strength to the cell.
(iii) It protects the plasma membrane and inner cell organelles by bounding the cell from outside.
(iv) It allows cell of plants, fungi and bacteria to withstand very dilute external media without bursting.
(v) It helps in transport of the material in and out of the cell.
(vi) Cell wall maintains the shape of the cell when cytoplasm shrinkes away from cell wall during plasmolysis.
(vii) It prevents desiccation of cells.

Difference

Difference

Example of osmosis:
(i) Absorption of water by plant roots.
(ii) Absorption of water by freshwater unicellular organisms such as Amoeba.

Robert Hooke (1665), Robert Hooke b chance observed a slice of cork through a self-designed microscope. He observed that it  contained many little compartments, like a honeycomb, which he named as cells.
However, Leeuwenhoek (1674) discovered the free-living cells in pond water for the first time, b y his improved microscope.

The following  three things could happen:
(i) If the solution surrounding the cell is very dilute than cytoplasm, the water will move into the cell, i.e., the cell will gain water.
(ii) If the solution has exactly similar water concentration as that of cytoplasm of cell, there will be no net movement of water across the cell membrane, i.e., no gain or loss of water from the cell.
(iii) If the medium (solution) has a lower concentration of water than the cell, i.e., the solution is concentrated, the cell will lose water by osmosis.