d. the living world. Biologists need to use the living world in order to back up the scientific method.
Ans.
Lac (lactose) operon in a type of bacterial operon, which shows a cluster of genes that are regulated by a single promoter. It is composed of an operator, promoter, a terminator, and three structural genes (lacA, lacY, and lacZ), which are responsible for the transport and breakdown of lactose.
The lac operon is an inducible operon as it gets activated in the presence of lactose and expressed its functional genes in the form of proteins (or enzymes) for lactose metabolism.
Thus, the correct answer to be fill in first blank is 'inducible' and in second blank is 'lactose.'
<h2>Answer:</h2>
Paramecium is the single celled organism (unicellular).
<h3>Explanation:</h3>
- An organism which contain only one cell is known as unicellular organism.
- Paramecium is the unicellular parasite. It can move and digest food.
- In its structure there are food vacuoles for the digestion of food.
- Paramecium is the eukaryotic organism because it has a well organised cell with distinct nuclear membrane.
- It belongs to kingdom protista.
