Which process uses proteins to move molecules against a concentration gradient?
a. active transport
b. passive transport
C. endocytosis
d. phagocytosis

the answer is "a.) well–developed vascular system."

explanation:

b. lithosphere, asthenosphere, mesosphere   is the answer most likely

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

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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: