Based on what you know about the relationship between the burning of fossil fuels (coal, oil, gasoline) and CO2, how could this also contribute to the cyclic nature of CO2 concentrations throughout the year?

Natalie had random hand movements when she was two months old. when she was six months old, she used to grab a block with her whole hand. now at the age of ten months, she can grasp the same block with her thumb and forefinger. this sequence of growth in her hand and finger movements is according to the pattern.

Epinephrine is a hormone released from the adrenal gland of the body, most often in a stressful situation. it is known as the "fight-or-flight" hormone. one way that it causes a response in the body is to activate receptors on muscle cells. where are these cellular receptors located? a. on the cell membrane b. in the nucleus c. on the cell wall d. around the mitochondria

Identify two examples of chemical reactions that you have encountered during the last week. identify an exothermic and endothermic reaction. explain.