Answer:
An amino acid activates the repressor so that the repressor binds to the operator and prevents transcription.
Explanation:
In an operon, promoter is followed by operator which is finally followed by the structural genes to be transcribed. RNA Polymerase binds to the promoter and initiates transcription. A repressor can negatively control the transcription process by binding to the operator so that the RNA Polymerase is not able to move forward and transcription is halted.
For example: in trp operon, tryptophan amino acid binds to the repressor molecule which leads to change in repressor's shape. The repressor is now able to bind to the operator and prevent transcription.
Answer:
Option (b).
Explanation:
Iguana and flying dragons are both reptiles. Iguana is a herbivorous lizard belongs to the order squamata. Flying dragons are known as gliding lizrds and belong to the genus<em> Draco. </em>
Iguana can easily be identified by their droopy skin, stocky stature and spines on their necks, backs, heads and tails. Iguanas may venture to the ground. Flying dragons has reduced tail, throat sacs color is different in males and females. Flying dragons used to live on trees, feed on the arboreal ants and will frequently venture in the ground.
Thus, the correct answer is option (B).
Answer:
2. Hip bones
Explanation:
More than 40 million years ago, whales had ancestors who walked on land. Even now, they have a feature they inherited from them - hip bones. Scientists used to think that they are vestigial, i.e. that they lost their function. However, recently they discovered that these bones help whales (and other marine mammals who have them, such as dolphins) maneuver better mating.
Whales developed the rest of the listed features later, when they became marine animals. This is why they are incorrect.
