153. Frost forms when:

A. Objects on the ground cool below the dew point temperature.
B. The dew point is 32oF or below.
C. Water vapor changes into ice without first becoming a liquid.
D. All of the above
✅ The correct answer is option D.
Frost forms when an outside surface cools past the dew point. The dew point is the point where the air gets so cold, the water vapour in the atmosphere turns into liquid.

155. IUCN (The International Union For Conservation Of Nature And Natural Resources) headquarters is at

A. Gland, Switzerland
B. Paris, France
C. Vienna, Austria
D. NewYork, USA
✅ The correct answer is option A.
Its headquarters are in Gland, Switzerland. IUCN has observer and consultative status at the United Nations and plays a role in the implementation of several international conventions on nature conservation and biodiversity.

159. All the statements are correct regarding ecological succession except

A. It is a random process
B. Species diversity increases as succession proceeds
C. The food chain relationships becomes more complex
D. The role of decomposers becomes more and more important
✅ The correct answer is option A.
All the statements are correct regarding ecological succession except that it is a random process.