Guillermo was finding it difficult to walk up the steps to his family’s apartment. His doctor thinks that his cells might not be getting enough oxygen or glucose. Why does having low levels of glucose or oxygen in his cells make it difficult for Guillermo to walk up steps? Which body systems should the doctor test in order to find out whether Guillermo’s cells are getting enough oxygen and glucose and why?

Sydney drew a flow chart to illustrate the nitrogen cycle.which labels best complete the flow chart? x: producers undergo photosynthesis.y: nitrogen compounds are released into the air.x: nitrogen compounds are released into the air.y: producers undergo photosynthesis.x: free nitrogen is in the atmosphere.y: producers absorb nitrogen compounds through their roots.x: producers absorb nitrogen compounds through their roots.y: free nitrogen is in the atmosphere.

Which of the following types of stars is most likely to end up as a supernova? in graph a, the curve peaks at 800 nm, in the red section of the visible light spectrum. in graph b, the curve peaks at 550 nm, in the green section of the visible light spectrum. in graph c, the curve peaks at 450 nm, in the blue section of the visible light spectrum. in graph d, the curve peaks at 300 nm, in the violet section of the visible light spectrum. a b c d

Consider the venn diagram of plant reproduction. where in this image, areas a - d, would you insert the picture of the orange lily?