How do Organisms Reproduce? — Science STD 10 — Question

What is hydroelectricity? Explain the basic principle of generation of hydroelectricity with the help of a labelled diagram.

An object is placed (a) 20cm, (b) 4cm, in front of a concave mirror of focal length 12cm. Find the nature and position of the image formed in each case.

What are the possible blood groups likely to be inherited by children born to a group A mother and a group B father? Explain your reasoning.

An object 5cm high is held 25cm away from a converging lens of focal length 10cm. Find the position, size and nature of the image formed. Also draw the ray diagram.

Two very small organisms X and Y both reproduce by the method of budding. Organism X is industrially very important because it is used in making alcohol from sugar. It is also used in making bread. Organism Y Lives in freshwater. If organism Y gets cut into a number of parts accidently, each cut part can grow to form complete organism.

1. What are organisms X and Y?
2. What is the name of the process in which X converts sugar into alcohol?
3. To which class of organisms does X belong?
4. Name an important body feature of organism Y.
5. Which organism is multicellular and which one is unicellular?

A salt X is formed and a gas is evolved when ethanoic acid reacts with sodium hydrogencarbonate. Name the salt X and the gas evolved. Describe an activity and draw the diagram of the apparatus to prove that the evolved gas is the one which you have named. Also, write chemical equation of the reaction involved.

X, Y, and Z are three animals. The animal X can fly but animal Y can only run on ground or walls. The forelimbs of animals X and Y have the same basic design but they are used for different purposes such as flying and running respectively. The animal Z became extinct an long time ago. The study of fossils of Z tells us that it had some features like those of X and some like those of Y. In fact, Z is said to form a connecting link in the evolutionary chain of X and Y.

1. What could the animals X, Y and Z be?
2. What name is given to the forelimbs like those of X and Y which have the same basic design but different functions?
3. Name one feature in which Z resembled X.
4. Name one feature in which Z resembled Y.
5. Which is the correct evolutionary chain involving X, Y and Z : X → Z → Y or Y → Z → X?

State one use each of the following non-metals:
Hydrogen, Carbon (as Graphite), Nitrogen, Sulphur

When the branches of a plant growing in the field are pulled towards the ground and a part of them is covered with moist soil (leaving the tips of the branches exposed above the ground), then after some time new roots develop from the parts of branches buried in the soil. On cutting these branches from the parent plant, new plants are produced from the cut parts of branches which had developed roots.

1. What is this method of propagation of plants known as?
2. What type of branches should a plant have to be able to be propagated by this method?
3. Name any two plants which are grown for their flowers and propagated by this method.
4. Name any two plants which are grown for their fruits and propagated by this method.
5. Name one plant which gets propagated by this method naturally by forming runners (soft horizontal stems running above the ground).