Birds eye view ANSWER ASAP

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

What mass of glucose is produced when 54g of water react with carbon dioxide

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.