The correct answer is A. Lac repressor.
Lac repressor prevents lac gene which are found in the DNA of Escherichia Coli from being expressed for many times.
Lac repressor is termed as DNA which binds proteins. It allows the expression of genes from coding which are made for proteins to be involved in metabolism of lactose which is in bacteria.
When there is no lactose which is available in the cell, then the genes are being repressed. Lactose are being converted to allolactose if they are available.
Do you have the multiple choices that go to this question?
A natural phenomenon that typically influences climate over a period of one to two years is sulfur-rich violent volcanic eruption.
Without any doubt, the most plentiful volcanic gas from a volcanic eruption is water vapor, which is non-dangerous.
Nevertheless, notable volumes of carbon dioxide, sulfur dioxide, hydrogen sulfide as well as hydrogen halides can also be released from volcanic eruptions. This natural phenomenon generally influences climate over a period of one to two years.
The sulfuric acid creates a mist of minute droplets in the stratosphere that reflects the incoming solar radiation, an thus is responsible for cooling of the Earth's surface.
These droplets can stay in the stratosphere for about three years, circulating all over through winds and resulting in consequential cooling all over the world.
To learn more about volcanic eruption here
brainly.com/question/1622004
#SPJ4
