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Solutions for Science, Class 10, CBSE
Asexual reproduction takes place through budding in
Yeast
Reason — Yeast can put out small buds that separate and grow further as an individual.
Which of the following is not a part of the female reproductive system in human beings?
Vas deferens
Reason — Vas deferens is a part of male reproductive system.
The anther contains
pollen grains
Reason — Anther contains pollen grains which has male gamete.
What are the advantages of sexual reproduction over asexual reproduction?
Following are the advantages of sexual reproduction over asexual reproduction:
What are the functions performed by the testis in human beings?
The functions performed by the testis in human beings are:
Why does menstruation occur?
In females, the ovary releases one egg every month, the uterus also prepares itself every month to receive a fertilised egg. Thus its lining becomes thick and spongy. This would be required for nourishing the embryo if fertilisation had taken place. In absence of fertilised eggs this lining is not needed any longer. So, the lining slowly breaks and comes out through the vagina as blood and mucous. This cycle takes place roughly every month and is known as menstruation.
Draw a labelled diagram of the longitudinal section of a flower.
Below labelled diagram shows the longitudinal section of a flower:
What are the different methods of contraception?
The different methods of contraception are:
How are the modes for reproduction different in unicellular and multicellular organisms?
Unicellular organisms generally reproduce by asexual methods like budding, binary fission, multiple fission, fragmentation, spore formation. Variation is not common in their progeny.
On other hand, multicellular organisms can divide by sexual as well as asexual methods. For example, vegetative propagation in plants is a means of asexual reproduction while all higher animals reproduce sexually. Variation is seen in sexually reproducing organisms.
How does reproduction help in providing stability to populations of species?
Reproduction helps in providing stability to populations of species in following ways:
What could be the reasons for adopting contraceptive methods?
The reasons for adopting contraceptive methods are:
What is the importance of DNA copying in reproduction?
The DNA in the cell nucleus is the information source for making proteins. If the information is changed, different proteins will be made. Different proteins will eventually lead to altered body designs. Therefore, the creation of a DNA copy is very important in reproduction.
Why is variation beneficial to the species but not necessarily for the individual?
Variation is not necessary for an individual but it is very important for survival of a species. A population of reproducing organisms or a species are suited to a particular niche. If there is no variation among individuals of a species they can be easily wiped out in case of drastic change in niche. However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive. Therefore, variations prevent the complete wiping out of species in adverse climatic changes in their niche.
How does binary fission differ from multiple fission?
Binary fission | Multiple fission |
---|---|
A cell divides into two daughter cells. | A cell divides to give many daughter cells. |
It occurs in favourable condition. | It occurs in unfavourable conditions. |
Cyst is not formed. | Usually a cyst is formed. |
Example: Amoeba, Leishmania | Example: Plasmodium |
How will an organism be benefited if it reproduces through spores?
Some of the advantages of reproduction through spores formation are:
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
More complex organisms have high level of tissue differentiation and these tissues are highly specialized in their functions. The body has organ-system level of organisation. They can regenerate few damaged tissues but cannot regenerate organ or organ sysytem. Therefore, more complex organisms cannot give rise to new individuals through regeneration. Regeneration is only possible in lower and simple organisms that do not show complex cellular differentiation.
Why is vegetative propagation practised for growing some types of plants?
Vegetative propagation is practised for growing some types of plants because:
Why is DNA copying an essential part of the process of reproduction?
The DNA in the cell nucleus is the information source for making proteins. If the information is changed, different proteins will be made. Different proteins will eventually lead to altered body designs. Therefore, the creation of a DNA copy is an essential part of the process of reproduction.
How is the process of pollination different from fertilisation?
Pollination | Fertilisation |
---|---|
Pollination is the transfer of pollen grains from anther of a flower to stigma of the same or a different flower. | Fertilisation is the fusion of male and female gametes resulting in the formation of a zygote. |
Pollination is a physical process. | Fertilisation is a biochemical process. |
External agents like wind, water, animals are required. | No external agent is required. |
It occurs in flowering plants only. | It occurs in almost all plants and animals also. |
What is the role of the seminal vesicles and the prostate gland?
The seminal vesicles and the prostate gland add their secretions along the path of vas deferens which makes transport of sperms easier and this fluid also provides nutrition to the sperms.
What are the changes seen in girls at the time of puberty?
The changes seen in girls at the time of puberty are:
How does the embryo get nourishment inside the mother’s body?
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 embryo’s side of the tissue. 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.
If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?
Copper-T is an Intrauterine Device (IUD) which is placed in the uterus to prevent pregnancy. It cannot prevent sexually-transmitted diseases.