Why does weather vary from day to day? Group of answer choices A. because the Sun's energy heats all parts of the Earth evenly but does not heat the atmosphere B. because weather is a complex interaction among many different variables that are constantly changing C. because the rotation of the Earth causes the atmosphere to expand and contract as it nears the Sun or Moon D. because cold fronts are always followed by a series of colder fronts, before a warm front returns

B. because weather is a complex interaction among many different variables that are constantly changing

Explanation:

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:

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.