Yes it is it usually
entirely
Each hydrogen bond will form ONE COVALENT bond with the other atoms in the molecule. Hydrogen has only one atom; to form a covalent bond, it has to donate one electron and the other atom that hydrogen is bonding with will donate one electron also, making two. These two electrons will be shared between the two, making the atoms to have two electrons each.
<span>Anton van Leeuwenhoek, </span>who designed and built the first microscope, also discovered microbes such as protozoa and bacteria from a drop of pond water. He also viewed bacteria taken from his teeth scrapings. He was also the first to discovered blood cells and human sperm cells.
Answer:
Membrane bound organelles ( Mitochondria, lysosome, Nucleus,..)
