CBSE 2025, Compartment, Set 1 Solutions
CBSE Biology (2025)

Diseases like pneumonia and common cold are caused by pathogens. Choose the option that correctly indicates the difference between Pneumonia and Common cold:

Identify the various parts, 'a', 'b' and 'c', in the given diagram of ovule:

Which of the following statements are true in respect of chorionic villi in humans? (i) It appears after implantation of human embryo in the uterus. (ii) It becomes interdigitated with cervical tissue of female reproductive tract. (iii) It increases the surface area for exchange of materials. (iv) It develops from the inner cell mass of blastocyst.

A man with a certain disease marries a normal woman. They have four children (three daughters and one son). All the daughters suffer from their father's disease but the son is not affected. Which of the following mode of inheritance do you suggest for this disease?

The chronological order of evolution of modern man from man-like primates is given below. Choose the option that indicates the evolution of man in correct order from early to recent times:

What would be the genotype of parents if the $F_1$ offspring have the phenotypes in 1:1 proportion?

Identify the material that helps in the precipitation of purified DNA during the process of isolation of DNA as shown in the given diagram.

Which of the following animals exhibit male heterogamety? (i) Fruit fly (ii) Fowl (iii) Human (iv) Honey bee

What would happen if in a gene encoding a polypeptide of 51 amino acids, codon present at 32 position (UAU) is mutated to UGA? Select the option that indicates the polypeptide with correct number of amino acids formed after mutation.

Given below is Column A with a list of certain Assisted Reproductive Technologies (ART), and Column B, with the procedures followed during ART:

Select the correct match:

What is the process of binding a primer to the denatured strand called?

Golden rice is a promising transgenic crop. When released for cultivation, it will help in:

Assertion (A): In bioreactors, raw materials are biologically converted into desired products. Reason (R): In bioreactors, optimum growth conditions for microbes such as temperature, pH, substrate, salts, etc. are available.

Select the correct option:

Assertion (A): All the events starting from pollen landing on stigma till pollen tube entering the ovule are included in pollen-pistil interaction. Reason (R): Pollen-pistil interaction ensures that only suitable pollens germinate on the stigma.

Select the correct option:

Assertion (A): DNA chemically is less reactive and structurally more stable when compared to RNA. Reason (R): DNA has 2'- OH group present at every nucleotide, which makes it more stable than RNA.

Select the correct option:

Assertion (A): Competition is a type of interspecific interaction between two or more species when the resources necessary for them are limited and adversely affect them. Reason (R): Special adaptation may allow the competing species to coexist in the same geographical area.

Select the correct option:

How many pollen grains and ovules are likely to be formed in the anther and the ovary of an angiosperm bearing 35 microspore mother cells and 35 megaspore mother cells respectively ?

How many meiotic divisions will a wheat plant undergo in order to produce 100 zygotes/100 grains? Calculate and give explanation.

Given below is a transverse sectional view of an apple. Label the following parts (i) and (ii) and write down their functions.

A couple believed that hospital authorities have exchanged babies and they have been given another baby by them. The wife is blood group 'A', her husband is blood group 'B' and the child is blood group 'O'. (i) Could the baby be theirs ? (ii) Justify your answer with the help of a cross.

Observe the diagram given below and answer the following questions.

(i) Name the molecule 'X' synthesized by 'i' gene. (ii) Which one of the structural genes codes for $\beta$-galactosidase? (iii) When will the transcription of this gene stop ?

Given below is the diagram representing the observation made for separating DNA fragments by gel electrophoresis. Observe the illustration and answer the questions that follow:

(a) DNA fragments move in the direction $A \rightarrow B$. Explain. (b) Name the matrix used and its role in gel electrophoresis. (c) Mention how the separated fragments can be visualized for further technical use.

(i) Draw a pyramid of numbers where a large number of insects are feeding on the leaves of a tree. What is the shape of this pyramid? (ii) Will the pyramid of energy also be of the same shape in this situation? Give reason for your response.

(i) What could be the reason for the fast rate of decomposition in the tropics? (ii) Identify 'x' and 'y' in the figure given below representing proportionate number of major vertebrate taxa.