Management Of Natural Resources — Science STD 10 — Question

A potted plant is growing in a transparent glass jar. In this plant, X and Y are the two growing parts having a lot of meristematic tissue. It is observed that the part X of this plant exhibits positive geotropism but negative phototropism. On the other hand, part Y of this plant exhibits negative geotropism but positive phototropism.

1. Name the part X of plant.
2. Name the part Y of plant.
3. Which part of the plant, X or Y, will exhibit positive hydrotropism?
4. Which part of the plant, X or Y, can have tendrils on it?
5. Which phytohormone causes the part X to exhibit negative phototropism?

Explain with diagrams what is meant by the “series combination” and “parallel combination” of resistances. In which case the resultant resistance is:

1. Less, and
2. More, than either of the individual resistances?

Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores.

State any five physical properties of metals and five physical properties of non-metals.

Explain the mechanism of photosynthesis.

Distinguish between pollination and fertilisation. Mention the site and product of fertilisation in a flower.
Draw a neat, labelled diagram of a pistil showing pollen tube growth and its entry into the ovule.

A population of red beetles lives in green bushes in a garden. Once during the process of breeding, a green beetle is produced.

1. State whether the change in colour of beetle is a process of evolution or not.
2. Can the new colour of green beetle be passed on to its next generations?
3. What will be the advantage (if any) of the green colour to the beetle?
4. State whether the production of green colour involved a change in genetic material or not.

CFL is costly as compared to the incandescent electric bulb. Even, then it is advised that incandescent bulbs should be replaced by CFLs. Why so?

The following diagram shows a part of the periodic table in which the elements are arranged according to their atomic numbers.
(The letters given here are not the chemical symbols of the elements):

a 3	b 4		c 5	d 6	e 7	f 8	g 9	h 10
i 11	j 12		k 13	l 14	m 15	n 16	o 17	p 18

1. Which element has a bigger atom, a or f?
2. Which element has a higher valency, k or o?
3. Which element is more metallic, i or k?
4. Which element is more non-metallic, d or g?
5. Select a letter which represents a metal of valency 2.
6. Select a letter which represents a non-metal of valency 2.