(a) 'r' is intrinsic rate of natural increase.
(b) With increases while a decrease in 'r' decreases the population size.

Restriction endonuclease enzymes are called molecular scissors which can cut double stranded DNA at specific sites.
Role of restriction endonuclease.
1. Restriction endonuclease inspects the length of DNA sequence.
2. It find specific recognition sequence i.e. Palindromic nucleotide sequence in DNA.
3. These enzymes cut the strand of DNA a little away from centre of palindromic sites.
4. Thus restriction endonucleases leave overhanging stretches called sticky ends on each strand.

The occurrence of higher temperature inside a greenhouse than outside, even though the interior receives less solar radiation, is called greenhouse effect.

A primer is a small segment of DNA that binds to a complementary strand of DNA.
Primers are necessary to start the functioning of DNA polymerase enzyme and, therefore, are necessary in polymerase chain reaction.

(a) Ori
Ori is a sequence of bases on DNA, from where replication of DNA starts.
Any piece of alien DNA linked to this sequence, can be made to replicate within the host cells; it is also responsible for controlling the copy number of linked DNA.
(b) \({ Amp }^{ R }\)
It is a selectable marker on the cloning vector pBR 322. If a segment of alien DNA is ligated at the Pvu I or P st I site of amp" gene, the recombinant will lose its ampicillin resistance (insertional inactivation); thus, the recombinants can be selected out from the non-recombinants.
(c) Rop
Rop codes for the proteins involved in the replication of the plasmid.

The curve I will explain the population growth of herbivores.in the absence of carnivores, the number of herbivores will keep on increasing exponentially; hence, an enormous population density is reached in a short time.

An electrostatic precipitator. It removes over 99% particulate matter present in the exhaust from a thermal power plant. It has electrode wires and a stage of collecting plates. The electrode, wires are maintained at several thousand volts, which produce a corona that releases electrons. These electrons attach to dust particles and give them a net negative charge within a very small fraction of a second. The collecting plates are grounded and attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall.

Golden rice is a genetically modified variety of rice. It contains 'beta carotene' genes from daffodil plant and also from some bacteria. Beta carotens is the building block of Vitamin A.Deficiency of vitamin A causes blindness.Thus, beta carotein present in golden rice can prevent blindness in children.

(ii) Cyanobacteria
(iii) Rahul is helpful in nature. He uses his knowledge for the benefit of society. Moreover, he is concerned to protect the environment from pollution as discouraged the use of chemical fertilisers.