Many scientific studies of dietary health effects are observational. compared to experimental studies, observational studies can extend over a longer time period, use a more representative population, and measure disease outcomes in addition to risk factors for disease. in an observational study, researchers enlist a study group, and use questionnaires and medical tests to quantify participants' health behaviors and status at the start of the study. the researchers continue to collect data on the participants over many years. information about each particpant's diet, lifestyle habits, risk factors, and disease outcomes are all recorded and analyzed. a landmark study of this type -- called the nurses' health study -- was begun in 1976 with more than 120,000 female nurses. data from a subset of this group (80,082 women) was used to study dietary fat intake from 1980 to 1994. one goal of that study was to measure the effect of dietary trans fats on cardiovascular health. do you understand how the nurses health observational study of dietary fats was set up and carried out? sort the statements into the appropriate bins depending on whether they represent factors that varied from participant to participant at the start of this study, factors that were consistent from the start of the study, and factors that were measured in the study.

answer: oof wait

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.

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.