Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Amensalism is an association between two species where :

Which one of the following is NOT a PCR-based molecular marker?

For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

The first line of immunity in our body is:

From which of the following bacteria, thermostable DNA polymerase is isolated?

The transfer of genetic material from one bacterium to another through the mediation of a vector like virus is termed as:

How many sentences are correct?

- To produce seeds without fertilisation is called apomixis

- Occurance of more than one embryo in a seed is referred to as polyembryony

- The pollen grains represent the male gametophytes.

Diacetyl morphine is commonly known as

What is false for Colostrum ?

Below are given in one column four methods of achieving contraception and in other column four methods of their working. Choose the correct match from Column-II with Column-I:

Column-I Methods	Column-II Working Methods
1. Pills	i. Inhibit the sperms to reach cervix
2. Condom	ii. Not allow the implantation
2. Vas deferens	iii. Stoppage of ovulation
3. Copper-T	iv. sperms in semen