What type of electrons is available to form bonds

Plz plz plz quick! 49 points for whoever which of the following statements about greenhouse effect is true? *life on earth is suffering because of greenhouse effect *the greenhouse effect is caused by human activity *all greenhouse gases are harmful *life on earth would not exist without the greenhouse effect

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism

In the diagram below, the northern hemisphere would be in what season at position a a. fall b. winter c. summer d. spring