Only the proteins that the bacteria escherichia coli (e. coli) needs are synthesized at any given time. for example, when lactose is available in the environment, e. coli will express the lac genes that allow it to break down lactose to obtain energy. when lactose is not present, these genes are not expressed. mc012-1.jpg which prevents the lac genes in the dna of e. coli from being expressed most of the time?

tissue

explanation:

it is actually formed by geoup of cells which is tissue

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.

sound moves fastest in solids because the molecules are tightly packed and it allows sound to vibrate