A. To increase productivity in the future
The biochemical analysis of different chlorophyll pigments in plants would be most useful in determining <span>D. which plants might have a common ancestor.
The field of biology that deals with the similarities between these plants is called comparative biochemistry. If these plants have similar DNAs, then they are more closely linked in evolutionary terms, and thus it is quite possible they have the same predecessor.
</span>
Answer:
Low level of nitrogen in the soil.
Adding organic materials poor in mineral nitrogen to the soil, which encourages the subsistence of soil microorganisms on mineral nitrogen to break down these materials, and this causes a temporary reduction in the proportion of mineral nitrogen in the soil.
Soil drought.
Problems with root growth due to soil compression or disease.