Transfer of pollen grains from the anther to stigma of another flower of the same plant is called geitonogamy . It is a type of self Pollination.

Hence the correct option is B.

● Autogamy -Transfer of pollen grains from the other to the stigma of the same flower is known as autogamy or self pollination.

● Xenogamy -is the transfer of pollen grains from the anther to the stigma of a different plant.

Hence the correct option is B.

 The most important sources of group B vitamins are beer yeast, liver, cereal seeds, green vegetables with leaves. Intestinal bacteria synthesizes group B vitamins, providing some of the body`s requirements. Bacterial synthesis is more intense in individuals fed with rations rich in milk and low in fats. Hence option C is correct.

Solution: The reaction of calcium with water is less violent. So, the heat released is not sufficient for the hydrogen to catch fire. Calcium starts floating because the bubbles of hydrogen gas which are formed during the reaction stick to the surface of the metal and hence calcium floats on water. Hence, option B is correct.

ADDITIONAL INFORMATION:  Lithium and sodium,have low densities and float on water. Rubidium and Caesium are denser and sink in water.

If a soft iron bar is inserted inside the solenoid, the magnetic field will increase because when current passes around it, the iron bar gets magnetized and achieve magnetic properties and it loses the magnetic properties as the current is switched off.

Hence the correct option is D.

ADDITIONAL INFORMATION

* The magnetic field inside the solenoid is uniform as these field lines are equally spaced and parallel inside circular curves of solenoid.

* The current-carrying solenoid behaves like a bar magnet when a steady current flows through it, the solenoid produced magnetic fields like the magnetic field produced by a bar magnet.

* The magnetic field inside the solenoid increases with increase in current by adding more turns to the coil of the current carrying wire and increases the strength of the field by increasing the amount of current.

Explanation: SI unit of electrical resistivity is ohm-metre.

=

SI unit of length is metre and area is .

Put the values in given formula

== ohm-metre= 

Hence the correct option is D.

ADDITIONAL INFORMATION:

• Electrical resistivity is a fundamental property which measures how firmly it resists the electric current.