All genes are not "on" all the time. using the metabolic needs of e. coli, explain why not. 2. what are the two main ways of controlling metabolism in bacterial cells? 3. feedback inhibition is a recurring mechanism throughout biological systems. in the case of e. coli regulating tryptophan synthesis, is it positive or negative inhibition? explain your choice. 4. what is a promoter? 5. what is the operator? what does it do? 6. what is an operon? ap biology reading guide chapter 18: regulation of gene expression fred and theresa holtzclaw copyright © 2010 pearson education, inc. - 2 - 7. list the three components of an operon, and explain the role of each one. 8. how does a repressor protein work? 9. what are regulatory genes? 10. distinguish between inducible and repressible operons, and describe one example of each type. 11. label this sketch of the lac operon with the terms at right. know the function of each structure.

the answer is c

explanation:

thinking it would be physical characteristics

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.