What has to happen to cause an object in orbit to fall toward earth?

If someone could do the first couple, just so i can see how it's done that would be great! 20 points. complete a dichotomous key for the 10 leaves on the common leaves sheet. the chart provided here allows for 11 pairs of statements. depending on how you build your dichotomous key, you may or may not need all of them, or you may need to add some.

Nucleic acid certain protein cell membranes certain carbohydrates

Lactic acid and energy are produced in muscle cells during choose 1 aerobic respiration cellular respiration anaerobic respiration cellular division