Questions

Plants are producers, which means they make their own food. Chloroplasts are organelles found in eukaryotic and plant cells that conduct photosynthesis. Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant.

Plants use energy from sunlight to help make their food, but they need chloroplasts to do it.

Hence, in plants, chloroplasts are necessary for Photosynthesis.

True, Stress is a factor that contributes to heart disease risk.

More factors that contributes to heart disease risk are blood pressure, cholesterol, smoking, physical inactivity and overeating.

Monopotassium tartarate was used in baking powder.

Labyrinth which is part of the ear is the main organ of balance in the human body.

Refractive Index of glass with respect to water can be calculated by 

(Refractive Index of glass with respect to air) × (1/Refractive Index of water with respect to air)

We know that,

Refractive Index of glass with respect to air = 4/3

Refractive index of water with respect to air = 3/2

Hence, Refractive Index of glass with respect to water = (4/3) x (2/3) = 8/9.

Resistivity :

Resistivity is a measure of the resistance to the flow of electrons. 

Conductivity :

Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.

Example:

Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance. 

A Telephone or an Alarm...