Answer:
In this given statement , the plastic base becomes negatively charged because plastic is an insulator . And the metal cup does not become charged because metal is a conductor.
Explanation:
<u>Reason behind , why plastic base becomes negatively charged -:</u> When a plastic base is rubbed with a dry cloth in the metal trophy, electrons are shifted from one material to the other. Thus, the substance that gains electrons (which is the plastic base) becomes negatively charged. thus , the plastic is an insulator , which causes charge (negative ) by rubbing.
<u>Reason behind , why the metal cup does not become charged -:</u> The metal cup is a conductor, and the surplus charge on the metal flows to the person who charges the cup and to the ground so that it is not charged. Thus, rubbing a metal can trigger hand\finger injury because metals generate excess heat in rubbing .
Answer:
Two or more elements,
Two or more elements,Chemically combined elements,
Two or more elements,Chemically combined elements,More and definite proportions.
Explanation:
A compoundcan be definedas a substance which is composed of two or more elements, that are combined together chemically.
These constituents elements are present in definite proportion and quantities. The composing elements of a compound can be separated only by the means of chemical procedures. A compound is composed of more than one type of atom.
Hence answer could be:
Two or more elements,
Two or more elements,Chemically combined elements,
Two or more elements,Chemically combined elements,More and definite proportions.
Answer:
cell wall, cell membrane, cytoplasm, vacuole, ER and nucleous
Explanation:
The correct answer is (B) Photosynthesis and diffusion from the air
Dissolved oxygen enters the water from photosynthesis and through air. The The aeration of water can be caused by wind. From the air oxygen diffuse into the water and gets mixed in the it through circulation. The oxygen is also produced as a waste product of photosynthesis from blue-green algae, phytoplankton, etc which is added in water.
