The heart is a muscular pump with two main functions: receive deoxygenated blood from the systemic circuit and then pump it to the lungs to get rid of the CO2 and pick up oxygen. The oxygenated blood comes back to the heart to be pumped out through the arterial system. Study how blood moves into and out of the heart.

b.

the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation:

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.