Yes, pH of the soil affects the colour of flower.
Flowering plants grown in acidic soil (pH<7) bears blue flowers or at has a blueish tint.
Whereas, Flowering plants grown in Neutral (pH=7) and Basic (pH>7) soil bears pink and red flowers.
A plant's flower color is determined by a complex balance between chlorophyll, beta carotene, flavonoids,etc in particular pH of the soil to give out vibrant colors like red, blue, pink, yellow,etc.
Xylem and phloem fiber cells
Parasitism is an interaction in while the host is harmed
The statement above is FALSE. In the scenario given above the doctor is working at the organ level. This is because, he is working with lung which is an organ that participates in breathing. The lung is an organ because it is made up of different tissues which are in turn made up of different cells.
Working at the cellular level involve working with cells. For instance, when a microbiologist is growing a cell in a culture, he is working at a cellular level.