There are some sticky wickets, however, that make it difficult to label this as a general rule.
The widespread use of phosphate-containing additives has substantially increased our daily phosphate intake, and the frequent absence of phosphate levels on food labels makes it difficult to ascertain the phosphate content of food.
However, the requirement of relatively large amount of RNA for labeling and hybridization makes it difficult to perform microarray experiments with limited biological materials, thus leads to the development of many methods for preparing and amplifying mRNA.
This makes it difficult to identify the everyday use of (different) nutrition labels and their influence on diet quality.
The absence of clear labeling means that the significance of these variables, if any, may be unclear, which makes it difficult to read and interpret the diagram.
"It obviously makes it difficult to shop".
"It makes it difficult to raise money".
That makes it difficult to recommend solutions.
It makes it difficult to form coalitions.
It makes it difficult to say anything.
