Q18 of 27 Page 1

Define pollination. Explain the different types of pollination. List two agents of pollination? How does suitable pollination lead to fertilization?

OR


(a) Identify the given diagram. Name the parts 1 to 5



(b) What is contraception? List three advantages of adopting contraceptive measure.


Pollination refers to the transfer of pollen grain from the anther to the stigma to allow fertilization to occur.

Types of pollination:


Self-pollination: the pollination of a flower by pollen from the same flower or from another flower on the same plant.


Cross pollination: it is the transfer of pollen from the flower of one plant to the flower of a plant having a different genetic constitution.


Agents of pollution are biotic or abiotic factors that help in pollination. Some agents of pollination are, insects, wind, water, etc.


The transfer of pollen from the anthers to the stigma of the flower is known as pollination. Pollination is required for fertilization. A tube grows out of the pollen grain and travels through the style, to reach the female germ cell in the ovary to cause fertilization.


pollination-clipart-stage-724019-8344368.jpg


OR


a) 1. Fallopian tube or Oviduct: It is responsible for carrying the mature ovum to the uterus. The oviduct is also the place where fertilization takes place.


2. Ovary: A pair of ovaries is present in the human female reproductive system. Ovaries produces ova (eggs/female gametes) Ovaries are also responsible for producing estrogen, which is a female hormone involved in the development of secondary sexual characters.


3. Uterus: Uterus or the womb is the place where the fertilised egg gets implanted and it nurtured. It holds and supports the developing foetus.


4. Cervix: It forms the neck of the uterus and opens into the vagina. The cervix functions as a path or the opening to the vaginal opening.


5. Vagina: It acts like a birth canal for childbirth and also serves as the opening through which menstrual blood exits.


b) Contraception is a method that is used to prevent conception or pregnancy. The major forms of contraceptives are condoms, contraceptive pills, IUDs etc.


Advantaged of adopting contraceptive measures are:


They help in population control


They help in avoiding unwanted pregnancies


They help in spacing out pregnancies.


They also sometimes help in regulating the menstrual cycle.


More from this chapter

All 27 →
16

(a) List in tabular form 3 chemical properties on the basis of which we can differentiate between a metal and a non-metal.

(b) Give reasons for the following:


(i) Most metals conduct electricity well.


(ii) The reaction of iron(II) oxide [Fe2O3] with heated aluminium is used to join cracked machine parts.


17

Write the chemical formula and name of the compound which is the active ingredient of all alcoholic drinks. List its 2 uses. Write chemical equation and name of the product formed when this compound reacts with-

(i) sodium metal


(ii) hot conc. Sulphuric acid


OR


What is methane? Draw its electron dot structure. Name the type of bonds formed in this compound. Why are such compounds:


(i)poor conductors of electricity? and


(ii) have low melting and boiling points? What happens when this compound burns in oxygen?


19

An object is placed at a distance of 60 cm from a concave lens of focal length 30 cm.

(i) use lens formula to find the distance of the image from the lens


(ii) List 4 characteristics of the image (nature, position, size, erect/inverted) formed by the lens in this case.


(iii) Draw ray diagram to justify you answer of part (ii).


20

(a) With the help of a suitable circuit diagram, prove that the reciprocal of the equivalent resistance of a group of resistances joined in parallel is equal to the sum of the reciprocals of the individual resistors.

(b) In an electric circuit 2 resistors of 12 Ω each are joined in parallel to the a 6V battery. Find the current drawn from the battery.


OR


An electric lamp of resistance 20Ω and a conductor of resistance 4Ω are connected to a 6V battery as shown in the circuit. Calculate:


(a) The total resistance of the circuit


(b) the current through the circuit


(c) the potential difference across the


(i) the electric lamp


(ii) conductor


(d) power of the lamp.