1) they have similar chemical properties.
for example fluorine from the 17th column is a non metal so does all the elements of that group.
2)they have same valence electrons in their outermost shell
example
electronic configuration of
hydrogen 1, lithium 2,1, sodium 2,8,1 and so on.
3) have same valency.
Answer: Cell membrane is layer which is present in all living cells. It is present under the cell wall but in some cases such as plant cells.
Explanation: It is composed of lipid bilayer and proteins embedded in it. Phospholipids, glycolipids and sterols is the composition. Its function is to protect the cell from extracellular environment. It is semipermeable membrane that js allow only selected molecules to pass.
ecosystem:
Living and Nonliving Things in the Ecosystem. Ecosystems -- biological communities -- include living organisms like animals, plants, insects and bacteria, as well as nonliving components like rocks, soil, water and sunlight.
Embryonic development involves process of formation and development of an embryo. In humans, during the early stages, 10 weeks of embryonic development, all the major body organs are formed.
Photosynthesis<span> makes the glucose that </span>cellular respiration<span> uses to make ATP</span>
