Answer:
Negatively repressible.
Explanation:
A control which occurs through repressor is known as negative control which may be inducible or repressible.
When a small molecule named as allolactose binds this repressor it leads to allosteric repulsion which removes repressor from the operator as a result of which RNA polymerase can start transcription. Allolactose is therefore known as inducer because it induces lac operon expression.
But here, the operator is active (induced) already so there is no need to induce the operon which means that it can only be repressed so that transcription could stop. So the answer is negatively repressible operon.
Answer:
Option-C
Explanation:
Scientists found a fossil of a fish with four limbs or legs. The fossil was estimated to be around 375 million years old.
The fossil showed the fins and scales of a fish but they also possess the bones of proto-wrist, shoulders and the elbow.
The presence of these bones can be a clue that the fish evolved the limbs to walk on the land and will later evolve into animals belonging to amphibians, reptiles and mammals. Therefore, the Tiktaalik is considered the missing link of how life evolved from water to land.
Thus, Option-C is correct.
Explanation:
base on which an organism lives the soil is the substrate of most seed plants. .A substance acted upon (as by an enzyme)
Answer:
c
Explanation:
etc uses oxygen
photosynthesis uses carbon dioxide