Question

most of the gaseous cycles are imperfect

Answer 1

It is False.

Gaseous Cycles are cycles where the reservoir is a natural atmosphere or the hydrosphere. Examples are - water cycle, carbon cycle, nitrogen cycle, etc.

A perfect nutrient cycle is one in which nutrients are replaced as fast as they are utilized. In most gaseous cycles, the gases are replaced as soon as they are utilized.  Therefore, all the gaseous cycles are usually considered as perfect cycles.

Sedimentary Cycles, where the reservoir is the earth’s crust elements like the cycles of phosphorous, sulfur, calcium, magnesium, etc. are considered as relatively Imperfect cycles. This is because some nutrients that are lost from the cycle get locked into sediments and thus, become unavailable for immediate cycling.

Answer 2

The statement is false.

A nutrient cycle in which the nutrients are replaced as fast as they are utilized is known as a perfect cycle. 

Based on the nature of the reservoir the cycles are classified as:

i. Gaseous cycle - Where the atmosphere or hydrosphere is the reservoir. For example, water cycle, nitrogen cycle and carbon cycle.

ii. Sedimentary cycle - Where the earth's crust or the elements found in earth's crust are the reservoir. For example, phosphorous cycle, calcium cycle, sulphur cycle and magnesium cycle.

Most gaseous cycles are considered as perfect cycles. While sedimentary cycles are considered to be relatively imperfect. In sedimentary cycles some nutrients get locked into sediments and become unavailable for immediate cycling.