Explanation:
It is less dense when frozen than when it's a liquid.
Water freezes at 0°C, therefore the water molecules form a lattice crystalline structure maintained by hydrogen bonding. This Ice formed is less dense than water because the orientation of hydrogen bonds causes molecules of the ice to push farther apart hence lowering its density.
It takes a lot of energy to raise the temperature of water.
Specific heat capacity is the energy is takes to raise 1 mole of a substance to °C. For water, its specific heat capacity = 4.18 kJ/kg°C
Water molecules sticks to each other.
Forces of cohesion is the property of water molecules to stick to each other. Also, Hydrogen bonds are formed between adjacent water molecules because of the positive charged hydrogen end of one water molecule attracts the negative charged oxygen end of another water molecule.
It is a good solvent because both polar and nonpolar molecules dissolve in it.
Water is a univeral solvent because it dissolves a lot of solute unlike any other solvent. Water does not dissolve non-polar molecules because no hydrogen bond can be formed between them.
It prepares to fight danger or run from it. It identifies the primary source of danger.
Answer:
The correct answer will be option-B.
Explanation:
Photosystem of a plant is complex pigment-protein molecules which absorbs the light energy required for the formation of a glucose molecule.
Two types of Photosystem are present in the plants which are: P₆₈₀ and P₇₀₀. The 680 and 700 denote the wavelength of the light energy absorbed by the pigment of the chloroplast. The electrons get excited only at their absorbing wavelength.
Thus, Option-B is the correct answer.
Answer:
They test or measure something.
Explanation:
Primary research articles report on research that has been completed. Therefore, a primary research article will review and analyze studies, and will state the research question and hypotheses of the studies presented. A primary research article does not test or measure anything, but will report on studies that do.