C is the answer i believe
Answer:
Hydrogen
Explanation:
Balloons are filled with light gases in order to make them float. Helium and Hydrogen are both light gases.
Helium is quite a lot lighter than air: it's about an eighth of the density of air. Hydrogen is about a sixteenth the density of air, so it'll float in air and will in fact float upwards.
Hydrogen however is twice as heavy as helium, but that doesn't mean the amount of lift off of the balloon is twice as much. The amount of lift is determined by the difference in density with respect to air.
Hydrogen is calculated to be less dense than helium, that explains why hydrogen filled balloons would go up higher.
Helium filled balloons are used because of the safety implications. The problem is that hydrogen is explosive may have some health and safety implications! Helium is much more safe to use.
Answer:
O(Oxygen)
Explanation:
2+2+4=8
And the eighth element of the periodic table is Oxygen
Suspension is defined as the heterogeneous mixture in which solute particles suspended throughout the bulk of the particles. The particle size is more than 100 nm. In suspension, particles don't pass through filter paper. Sand in water is an example of suspension.
Colloid is defined as a mixture (heterogeneous and homogeneous) in which one substance of dispersed insoluble particles get suspended throughout other substance. The particle size is 1 to 100 nm. In colloid, particles are small, thus pass through filter paper. The particles of air which is dispersed in solid stone is an example colloid.
Emulsion is a mixture of two or more substance which are immiscible in nature. It is a part of colloid. Milk is an example of emulsion.
Solution is a homogeneous mixture with clear or transparent appearance. The particle size in solution is 
i.e. molecule in size. There is no effect of light occurs in the solution and solution can't filtered but can separated by the physical technique i.e. distillation.
Answer:
1. active site
2. substrate.
3. activity
4. cofactor
5. complex
6. coenzyme.
Explanation:
1. A substrate binds to an enzyme at the active site where the reaction occurs.
2. In a catalyzed reaction, a reactant is often called a substrate.
3 activity is a measure of how fast an enzyme can convert the reagent to the product.
4. An inorganic substance necessary for the function of some enzymes is called a cofactor.
5. When properly aligned, the enzyme and substrate form an enzyme-substrate (ES) complex.
6. A small organic molecule necessary for the function of some enzymes is called a coenzyme.
