Question 4 of 20 : Select the best answer for the question
4. How do soils become overly saline?
O A. Salt from fertilizer accumulates in the soil.
O B. Plains are flooded with seawater during large storms, which evaporates.
O C. Salts accumulate as water evaporates in poorly drained arid fields.
O D. As the climate warms, salts are deposited with acid rain.
O Mark for review (Will be highlighted on the review page)
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compost can be added to topsoil as a:

pesticide

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

because they are eaten by the frog and the frog getseaten by the snake and the snake by the eagle