A student comes to school and eats breakfast before going to class. Eating breakfast gives the student sufficient energy to handle her classes. What two body systems work together to provide the student’s cells with energy?   
A. 
Excretory and endocrine
B. 
Digestive and circulatory
C. 
Digestive and excretory
D. 
Excretory and circulatory 


Plants are used for so many things. in your house alone, you can probably look around you and see where plants have been used. for this project, you will identify various uses of plants in your home. directions make a list of objects, products, and any other items around your house where plants were involved in the production of the item. you should have a list of at least twenty items. then respond to the following questions: note: your list of objects and the answers following should be at least 200 words in length. what if plants no longer existed on earth? how would your life be different?

1. variations in a population of moths allow for some of its members to be able to adapt to environmental changes. the better adapted of the moths will be able to survive the change and thus prevail as the “fittest” of the species. (a) describe three mechanisms in which variation can occur within a species population. (b) explain which mechanism or mechanisms would be responsible for the survival of a population of peppered moths better than white moths in an environment affected by industrial soot. justify your answer.

If a strand of dna has 35% thymine. what is the percentage of cytosine, adenine, guanine?