Questions

To reduce the risk of bacterial contamination, many foods must be stored in the refrigerator and thus kept below 5 degrees Celsius. These foods are often classified as ‘high-risk foods’ and include – meat, poultry, dairy, seafood, eggs, smallgoods and cooked rice and pasta. This also refers to ready-to-eat foods that have high-risk foods as ingredients and include – casseroles, quiche, pasta salad, pizza, sandwiches and many cakes.

By keeping these high-risk foods under 5 degrees Celsius it stops them from entering the ‘danger-zone’ – temperatures between 5 degrees Celsius and 60 degrees Celsius. The danger-zone is the temperature zone which provides bacteria with the perfect environment to rapidly grow and multiply to numbers that cause food poisoning.

In biology, Homology is defined as any characteristic of biological organisms that is derived from a common ancestor. 

Hence, Homology is evidence of Common ancestry.

The photoelectric effect pointed to the particle properties of light, which had been considered to be a wave phenomenon. Particles like electron and protons have both particle like and wave like behavior. Thus, according to de Broglie, all the material particles in motion possess wave characteristics. Although the dual nature of matter is applicable to all material objects but it is significant for microscopic bodies only.

Ans. Let radius of the base and height of the cone be ‘r’ & ‘h’ respectively.

Then volume of cone = πr2h/3 For cylinder, radius is reduced by 4 times = r/4 And,  height is increased by 8 folds = 8h Volume of cylinder = πR2H = π(r/4)2 (8h) = (16/8)πr2h = πr2h/2 Ratio of volume of cone to volume of cylinder = (πr2h/3) : (πr2h/2) Or, Ratio = 2 : 3.