Which correctly describes crossing over? the process whereby non-sister chromatids exchange genetic material
the process whereby homologous chromosomes are pulled to opposite poles of the cell
the process whereby sister chromatids are pulled to opposite poles of the cell
the process whereby homologous chromosome pairs align randomly along the metaphase plate

it has one origin of replication, but it proceeds in two directions - d)

that would be called plucking : )

explanation:

''plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large "joint blocks". as a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock."

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:

im not intirely sure but i think the anwser is d relative humidity