Explanation:
Protandry - Male reproduction organ/anthers androecia/ stamens mature earlier than female reproduction organ/ carpels/ stigma/ pistil/ gynoecium in a flower. (ii) Self sterility - pollen grains are sterile to stigma of the same plants or same flowers.
I hope it's helpful for you.....
Explanation:
Scientists didnt belive that there are cells untill robert hooke (1665). He observed the cells in a cork slice with the help of a PRIMITIVE microscope
Leeuwenhoek (1674), with the help of an improved microscope, discovered free living cells in pound water for the first time.
It was robert brown in (1831) who discovered the nucleus in the cell.
Purkinjie in 1839 coined the term 'protoplasm' for the fluid substance of the cell.
THE CELL THEORY, that all plants and animals are composed of cells and that the cell is the basic unit of life, was presented by two biologists, schleiden (1838) and schwann(1839). The cell theory was fuether expanded by virchow (1855) by suggesting that all cells aris form PRE-EXISTING cells. With the discovery of the electron microscope in 1940,it was possible to observe and understand the complex structure of the cell and its various organelles.
Well, thats the history of the discovery of cells.
<span>The high surface tension helps the paper clip - with muchhigher density - float on the water. The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules.</span>
Arteries are blood carrying vessels which have thick, elastic, muscular walls, have no valves and in which blood flows under high pressure. The make up of arteries is unique to their function of transporting blood under high pressure.
All arteries carry oxygenated blood from the heart to all other parts of the body, with the exception of the pulmonary artery which carries de-oxygenated blood from the heart to the lungs. It is the only artery that transports blood which has not been oxygenated.
