Over time, a tree that once had a total mass of 300 g increased in mass to 3000 kg. This increase
in mass comes mostly from
(1) carbon dioxide that enters through the leaf
openings
(2) oxygen that enters through the leaf openings
(3) soil that all plants need to grow
(4) chloroplasts that enter the roots and move to
the leaves

WHAT IS I

carbon dioxide that enters through the leaf

openings

Explanation:

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.