State whether the following statements are True/False
Question: State whether the following statements are True/False 1. External fertilisation can occur both in water and on land. 2. The eggs of fish are covered by hard shells for protection. 3. Human egg has a head, middle piece and tail. 4. In adult human females, a single mature egg is released into an oviduct every month. Solution: 1. False, external fertilisation occurs only in water and not on land. 2. False, the eggs of fish are covered by gelatinous or jelly-like covering for protection. 3...
Read More →How is reproduction in Hydra
Question: How is reproduction in Hydra different from that in Amoeba? Solution: Both Hydra and Amoeba reproduce asexually involving only single parent but the mode of reproduction is different. Hydra reproduces from bulges or buds arising from the parent body that grows and matures into another organism, i.e. by budding, while Amoeba reproduces by binary fission, i.e. splitting of parent organism to form two new organisms....
Read More →Mother gives birth to a baby
Question: Mother gives birth to a baby but the baby has characters of both parents. How is this possible? Solution: Although, mother gives birth to a baby but the baby is formed from the fertilisation of male and female gamete that comes from the father and mother, respectively. The nuclei of both the parent gametes fuse to form a zygote with new character combinations from both parents. Hence, the zygote formed from fertilisation have characters of both the parents. This zygote develops inside ...
Read More →If Sn denotes the sum of the cubes of the first n natural numbers and sn
Question: If $S_{n}$ denotes the sum of the cubes of the first $n$ natural numbers and $s_{n}$ denotes the sum of the first n natural numbers then find the value of $\sum_{k=1}^{n} \frac{S_{k}}{S_{k}}$ Solution: Given in the question, Sn denotes the sum of the cubes of the first n natural numbers. sn denotes the sum of the first n natural numbers. Note: I. Sum of first n natural numbers, 1 + 2 +3+n, $\sum_{k=1}^{n} k=\frac{n(n+1)}{2}$ II. Sum of squares of first $n$ natural numbers, $1^{2}+2^{2}...
Read More →The term ‘metamorphosis’
Question: The term metamorphosis is not used while describing human development. Why? Solution: The term metamorphosis is not used while describing human development because in human beings, body parts of an adult are present from the time of birth itself, i.e. while beginning of life as a baby and until you are an adult, the basic plan of body does not change. On the contrary, in metamorphosis, the parts of the adult are different from those at the time of birth....
Read More →Fill up the blanks with the terms given below:
Question: Fill up the blanks with the terms given below: body, asexual, binary, single, nucleus Amoeba is a.. celled organism. It reproduces by reproduction. The process of reproduction begins by the division of its.. into two. This is followed by the division of its into two. This type of reproduction is called fission. Solution: Single,asexual, nucleus, body, binary...
Read More →The eggs of frogs do not have
Question: The eggs of frogs do not have shells for protection, yet they are safe in water, how? Solution: Frogs eggs are without any external covering or shell but a layer of jelly hold the eggs together, thus providing them protection. This jelly or gelatinous covering also protects them from drying up and prevents them from being eaten up by other animals or predators....
Read More →In markets, eggs of birds are
Question: In markets, eggs of birds are available but never eggs of dogs, why? Solution: Birds are oviparous, i.e. lay eggs outside their body. So, it is easy to collect their eggs and these are thus available in market. On the contrary, dogs are viviparous, i.e. do not lay eggs but give birth to young ones. Their eggs are extremely small which remain inside their bodies....
Read More →What is the importance of reproduction?
Question: What is the importance of reproduction? Solution: Reproduction is important for organisms because it ensures the continuity of life on earth. It is the means of multiplication and perpetuation of a species. It also creates variations among the population....
Read More →Although two cells called gametes fuse,
Question: Although two cells called gametes fuse, the product formed is a single cell called zygote. Justify. Solution: During fertilisation, only the nuclei of male and female gametes fuse. The sperm reaches to egg and only its nucleus enters the egg cell and fuses with the egg nucleus to form the single-celled structure called zygote. The cell formed consists of only one nucleus but is diploid in nature....
Read More →In human beings, the correct sequence
Question: In human beings, the correct sequence of events during reproduction is (a) gamete formation, fertilisation, zygote, embryo (b) embryo, zygote, fertilisation, gamete formation (c) fertilisation, gamete formation, embryo, zygote (d) gamete formation, fertilisation, embryo, zygote Solution: (a) In human beings, sexual reproduction takes place by the combination of gametes, i.e. sperm and egg, formed in male and female, respectively. The fusion of gametes is called fertilisation. The fusio...
Read More →For the function
Question: For the function $y=x^{2}$, if $x=10$ and $\Delta x=0.1$. Find $\Delta y$. Solution: $y=x^{2}$ $\Delta x=0.1$ $x=10$ $\frac{d y}{d x}=2 x$ $\Rightarrow\left(\frac{d y}{d x}\right)_{x=10}=20$ $\Rightarrow \Delta y=d y=\frac{d y}{d x} d x=20 \times 0.1=2$...
Read More →After fertilisation, the resulting
Question: After fertilisation, the resulting cell which gives rise to a new individual is the (a) embryo (b) ovum (c) foetus (d) zygote Solution: (d) After fertilisation (i.e. combining of sperm with the egg), zygote is formed. It is the beginning of formation of a new individual. All the multicellular animals start their life from a single cell called zygote....
Read More →Solve this
Question: If $\mathrm{S}_{\mathrm{k}}=\frac{(1+2+3+\ldots \mathrm{k})}{\mathrm{k}}$ prove that , $\left(\mathrm{S}_{1}^{2}+\mathrm{S}_{2}^{2}+\cdots \mathrm{S}_{\mathrm{n}}^{2}\right)=\frac{\mathrm{n}}{24}\left(2 \mathrm{n}^{2}+9 \mathrm{n}+13\right)$ Solution: Given, $\mathrm{S}_{\mathrm{k}}=\frac{(1+2+3+\cdots \mathrm{k})}{\mathrm{k}}$ To prove: $\left(\mathrm{S}_{1}{ }^{2}+\mathrm{S}_{2}{ }^{2}+\cdots \mathrm{S}_{\mathrm{n}}{ }^{2}\right)=\frac{\mathrm{n}}{24}\left(2 \mathrm{n}^{2}+9 \mathrm{...
Read More →Aquatic animals in which fertilisation
Question: Aquatic animals in which fertilisation occurs in water are said to be (a) viviparous without fertilisation (b) oviparous with external fertilisation (c) viviparous with internal fertilisation (d) oviparous with internal fertilisation Solution: (b) The aquatic animals in which fertilisation occurs in water are oviparous with external fertilisation. They lay eggs and release sperms outside body in the water for fertilisation to take place. The young one top is formed outside the body in ...
Read More →In human beings, after fertilisation,
Question: In human beings, after fertilisation, the structure which gets embedded in the wall of uterus is (a) ovum (b) embryo (c) foetus (d) zygote Solution: (b) After fertilisation, the zygote divides repeatedly to form a ball of hundreds of cells called an embryo. The embryo moves down from oviduct into the uterus, where it gets embedded. This is called implantation....
Read More →Which of the following statements
Question: Which of the following statements about reproduction in humans is correct? (a) Fertilisation takes place externally (b) Fertilisation takes place in the testes (c) During fertilisation, egg moves towards the sperm (d) Fertilisation takes place in the human female Solution: (d) Fertilisation in humans takes place in the female body. The sperms of man are introduced by penis into females body through vagina. The sperms then pass through the uterus and reach to oviducts. It is here, that ...
Read More →The approximate change in the volume
Question: The approximate change in the volume of a cube of sidexmetres caused by increasing the side by 2%, is ______________. Solution: Let ∆xbe the change insidexand ∆Vbe the change in the volume of the cube. It is given that, $\frac{\Delta x}{x} \times 100=2$ .....(1) Now, Volume of the cube of side $x, V=x^{3}$ $V=x^{3}$ Differentiating both sides with respect tox, we get $\frac{d V}{d x}=3 x^{2}$ $\therefore \Delta V=\left(\frac{d V}{d x}\right) \Delta x$ $\Rightarrow \Delta V=3 x^{2} \Del...
Read More →Reproduction by budding takes place in
Question: Reproduction by budding takes place in (a) Hydra (b) Paramecium (c) Amoeba (d) Bacteria Solution: (a) In Hydra, reproduction takes place by budding. A small part of the body of an organism grows as bud which then detaches and becomes a new organism. The other options Amoeba, Paramecium and bacteria reproduce asexually by binary fission....
Read More →The approximate change in the volume
Question: The approximate change in the volume of a cube of sidexmetres caused by increasing the side by 2%, is ______________. Solution: Let ∆xbe the change insidexand ∆Vbe the change in the volume of the cube. It is given that, $\frac{\Delta x}{x} \times 100=2$ .....(1) Now, Volume of the cube of side $x, V=x^{3}$ $V=x^{3}$ Differentiating both sides with respect tox, we get $\frac{d V}{d x}=3 x^{2}$ $\therefore \Delta V=\left(\frac{d V}{d x}\right) \Delta x$ $\Rightarrow \Delta V=3 x^{2} \Del...
Read More →Animals exhibiting external fertilisation
Question: Animals exhibiting external fertilisation produce a large number of gametes. Pick the appropriate reason from the following. (a) The animals are small in size and want to produce more offsprings (b) Food is available in plenty in water (c) To ensure better chance of fertilisation (d) Water promotes production of large number of gametes Solution: (c) A large number of gametes are released by such animals to ensure better chance of fertilisation. Since, the gametes are laid in water, man...
Read More →In the list of animals given below,
Question: In the list of animals given below, hen is the odd one out.Human being, cow, dog, hen. The reason for this is (a) it undergoes internal fertilisation (b) it is oviparous (c) it is viviparous (d) it undergoes external fertilisation Solution: (b) Hen is odd one out because it is oviparous, i.e. it lays egg from which young ones are hatched later on. The rest three (human being, cow and dog) are viviparous, i.e. give birth to young ones after they are fully developed....
Read More →In humans, the development
Question: In humans, the development of fertilised egg takes place in the (a) ovary (b) testis (c) oviduct (d) uterus Solution: (d) The development of fertilised egg takes place in the uterus (womb). The embryo gets embedded in the wall of the uterus for development by implantation....
Read More →Sets of reproductive terms are given below.
Question: Sets of reproductive terms are given below. Choose the set that has an incorrect combination. (a) Sperm, testis, sperm duct, penis (b) Menstruation, egg, oviduct, uterus (c) Sperm, oviduct, egg, uterus (d) Ovulation, egg, oviduct, uterus Solution: (c) Set (c) has an incorrect combination. This is because it has parts of both male and female reproductive system. Sperm is the male gamete while oviduct, egg and uterus are parts of female reproductive system....
Read More →If the solve the problem
Question: If $y=x^{3}+5$ and $x$ changes from 3 to $2.99$, then the approximate change is $y$ is ______________ Solution: Let $x=3$ and $x+\Delta x=2.99$ $\therefore \Delta x=2.99-3=-0.01$ $y=x^{3}+5$ (Given) Differentiating both sides with respect tox, we get $\frac{d y}{d x}=3 x^{2}$ $\Rightarrow\left(\frac{d y}{d x}\right)_{x=3}=3 \times(3)^{2}=27$ $\therefore \Delta y=\left(\frac{d y}{d x}\right) \Delta x$ $\Rightarrow \Delta y=27 \times(-0.01)=-0.27$ Thus, the approximate change inyis 0.27....
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