How are the modes for reproduction different
[question] Question. How are the modes for reproduction different in unicellular and multicellular organisms ? [/question] [solution] solution: Unicellular organisms reproduce by binary fission (e.g. Amoeba, Paramecium), multiple fission (e.g. Plasmodium), budding (e.g. Yeast), spore formation (e.g. Bacteria, Amoeba), but multicellular organisms reproduce by means of budding (e.g. Hydra), fragmentation (e.g. Spirogyra), regeneration (e.g. Hydra), vegetative propagation in all plants and sexual r...
Read More →What does the path of an object look like when it is in uniform motion ?
[question] Question. What does the path of an object look like when it is in uniform motion ? [/question] [solution] Solution: In uniform motion, the object moves along a straight path i.e. the path of object is a straight line. [/solution]...
Read More →What are the different methods of contraception?
[question] Question. What are the different methods of contraception? [/question] [solution] solution: Different methods of contraception can be classified into four categories : (i) Barrier method in which sperms are prevented to come in contact with ovum to avoid fertilization, this is used by male in the form of condoms and females in the form of cervical cap. (ii) Chemical methods- Some hormonal pills are available for females which are hormonal preparation and inhibit process of ovulation. ...
Read More →What does the odometer of an automobile measure?
[question] Question. What does the odometer of an automobile measure? [/question] [solution] Solution: Odometer measures the distance travelled by the automobile. [/solution]...
Read More →(i) For which values of a and b does the following pair of linear equations have an infinite number of solutions?
[question] Question. (i) For which values of a and b does the following pair of linear equations have an infinite number of solutions? 2x + 3y = 7 (a – b) x + (a + b) y = 3 a + b – 2 (ii) For which value of k will the following pair of linear equations have no solution? 3x + y = 1 (2k – 1) x + (k –1) y = 2k + 1. [/question] [solution] Solution: (i) 2x + 3y – 7 = 0 ...(i) (a – b) x + (a + b) y – (3 a + b – 2) = 0 ...(ii) For infinite number of solutions, we have $\frac{\mathbf{a}-\mathbf{b}}{\mat...
Read More →Draw a labeled diagram of the longitudinal
[question] Question. Draw a labeled diagram of the longitudinal section of a flower. [/question] [solution] solution: [/solution]...
Read More →Which of the following is true for displacement ?
[question] Question. Which of the following is true for displacement ? (a) It cannot be zero. (b) Its magnitude is greater than the distance travelled by the object. [/question] [solution] Solution: None of the statements (a) or (b) is true for displacement. [/solution]...
Read More →Why does menstruation occur?
[question] Question. Why does menstruation occur? [/question] [solution] solution: It occurs when egg produced is not fertilized. So thick and soft lining of uterus breaks down, shedding blood along with mucous which comes out of vagina in form of bleeding. [/solution]...
Read More →What are the functions performed
[question] Question. What are the functions performed by the testes in human beings? [/question] [solution] solution: Testes are responsible for production of sperms and testosterone hormone. [/solution]...
Read More →What are the advantages of sexual reproduction
[question] Question. What are the advantages of sexual reproduction over asexual reproduction ? [/question] [solution] solution: (i) Sexual reproduction is better than asexual reproduction because it brings variation which is necessary to have in a population so in case of adversity of environment all the member does not die but members with suitable variation survive to save the population from getting extinct. (ii) These variation collected over a period of time leads to formation of new speci...
Read More →Which of the following pairs of linear equations has unique solution, no solution, or infi nitely many solutions.
[question] Question. Which of the following pairs of linear equations has unique solution, no solution, or infi nitely many solutions. In case there is a unique solution, find it by using cross multiplication method. (i) x – 3y – 3 = 0 3x – 9y – 2 = 0 (ii) 2x + y = 5 3x + 2y = 8 (iii) 3x – 5y = 20 6x – 10y = 40 (iv) x – 3 y – 7 = 0 3x – 3y – 15 = 0 [/question] [solution] Solution: (i) x – 3y – 3 = 0, 3x – 9y – 2 = 0 $\frac{a_{1}}{a_{2}}=\frac{1}{3}, \frac{h_{1}}{b_{2}}=\frac{-3}{-9}=\frac{1}{3},...
Read More →The anther contains
[question] Question. The anther contains (A) Sepals (B) Ovules (C) Carpel (D) Pollen grains. [/question] [solution] solution: (D) Pollen grain [/solution]...
Read More →Under what condition is the magnitude
[question] Question. Under what condition is the magnitude of average velocity of an object equal to its average speed ? [/question] [solution] Solution: When an object moves along a straight path without change in its direction, the average velocity of an object is equal to its average speed. [/solution]...
Read More →Which of the following is not a part of the female
[question] Question. Which of the following is not a part of the female reproductive system in human beings ? (A) Ovary (B) Uterus (C) Vas deferens (D) Fallopian tube [/question] [solution] solution: (C) Vas deferens. [/solution]...
Read More →Distinguish between speed and velocity.
[question] Question. Distinguish between speed and velocity. [solution] [question] Solution: Speed is rate of change of distance, while velocity is the rate of change of displacement. Speed is a scalar quantity, while velocity is a vector quantity. Speed is always positive, while velocity is positive, negative or zero. [solution]...
Read More →Asexual reproduction takes place
[question] Question. Asexual reproduction takes place through budding in (A) Amoeba (B) Yeast (C) Plasmodium (D) Leishmania. [/question] [solution] solution: (B) Yeast [/solution]...
Read More →If a woman is using a copper-T,
[question] Question. If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases? [/question] [solution] solution: No,sexually transmitted diseases occur due to fluid to fluid contact that takes place in the vagina. [/solution]...
Read More →A farmer moves along the boundary of a square field
[question] Question. A farmer moves along the boundary of a square field of side 10 m in 40 s. What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds ? [question] [solution] Solution: The perimeter of square field $\mathrm{ABCD}=4 \times 10 \mathrm{~m}=40 \mathrm{~m}$. Time for moving around the $10 \mathrm{~m}$ square field once $=40 \mathrm{~s}$. Time for journey of farmer $=2 \mathrm{~min}$ and $20 \mathrm{~s}=140 \mathrm{~s}$. Number of times the farmer m...
Read More →How does the embryo get nourishment
[question] Question. How does the embryo get nourishment inside the mother’s body? [/question] [solution] solution: The embryo gets nutrition from the mother's blood with the help of a special tissue called placenta. This is a disc which is embedded in the uterine wall. It contains villi. On the mother's side are blood spaces, which surround the villi. This provides a large surface area for glucose and oxygen to pass from the mother to the embryo. [/solution]...
Read More →What are the changes seen in girls at the
[question] Question. What are the changes seen in girls at the time of puberty? [/question] [solution] solution: Following are the changes seen in female at the time of puberty A. Growth of hair under armpits and pubic region. B. Darkening of pubic region. C. High pitch voice. D. Growth and development of breast. E. Darkening of area around nipples. F. Onset of menstrual cycle. [/solution]...
Read More →An object has moved through a distance. Can it have zero displacement?
[question] Question. An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example. [/question] [solution] Solution: Yes, an object which has moved through a distance can have zero displacement. Example : When a person, walking along a circular path, returns back to the starting point, after completing a circle, his displacement is zero. But he covers a distance 2r, where 'r' is the radius of circular path. [/solution]...
Read More →What is the role of the seminal vesicles
[question] Question. What is the role of the seminal vesicles and the prostate gland? [/question] [solution] solution: Seminal vesicles are responsible for adding a fluid medium to sperms and provides nutrition for sperms whereas prostate gland adds fluid for their motility, maintaining pH in female reproductive tract. [/solution]...
Read More →How is the process of pollination different
[question] Question. How is the process of pollination different from fertilisation? [/question] [solution] solution: [/solution]...
Read More →Form the pair of linear equations in the following problems, and find their solutions (if they exist) by the elimination method :
[question] Question. Form the pair of linear equations in the following problems, and find their solutions (if they exist) by the elimination method : (i) If we add 1 to the numerator and subtract 1 from the denominator, a fraction reduces to 1 . It becomes $\frac{\mathbf{1}}{\mathbf{2}}$ if we only add 1 to the denominator. What is the fraction? (ii) Five years ago Nuri was thrice as old as Sonu. Ten years later, Nuri will be twice as old as Sonu. How old are Nuri and Sonu? (iii) The sum of the...
Read More →Explain how animals in Vertebrata are classified into further subgroups.
[question] Question. Explain how animals in Vertebrata are classified into further subgroups. [/question] [solution] Solution: Animals in Vertebrata are classified into five classes: (i) Class Pisces: This class includes fish such as Scoliodon, tuna, rohu, shark, etc. These animals mostly live in water. Hence, they have special adaptive features such as a streamlined body, presence of a tail for movement, gills, etc. to live in water. (ii) Class Amphibia: It includes frogs, toads, and salamander...
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