Physical and Chemical Changes — Science STD 7 — Question

The distances travelled by a car at various time intervals are given as follow

Distance (m)	0	5	10	15	20	25
Time (s)	0	2	4	6	8	10

(a) Draw the distance-time graph for the car.
(b) What conclusion do you get from this graph about the nature of motion of the car?

What precautions should you take while reading a clinical thermometer?

State the main agents of weathering.

Explain the process of reproduction in plants, involving the fusion of cells from male and female parts of a flower.

Explain how animals dwelling in the forest help it grow and regenerate.

What is groundwater? What are the sources of water which are fed by groundwater?

Given below is a jumbled sequence of the processes involved in a wastewater treatment plant. Arrange them in their correct sequence.
(i)Sludge is scraped out and skimmer removes floating grease.
(ii)Water is made to settle in a large tank with a slope in the middle.
(iii)Large objects like plastic bags are removed by passing wastewater through bar screens.
(iv)Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.
(v)Wastewater enters a grit and sand removal tank.

“Forest is a dynamic entity, full of life and vitality”. Explain briefly.

Describe the transport system in plants in detail.