Sound — Science STD 8 — Question

State whether human beings reproduce by sexual method of asexual method.

What is acne?

A car is moving towards North. What will be the direction of force of friction acting on this car due to surface of road?

Name a single cell (other than Ameoba cell) which can change its shape.

Name any five threatened wild animals which are protected and preserved in our wildlife Sanctuaries.

A nine-year-old boy is 120 cm tall. If the present height of boy is 75% of his full height, calculate the full height which the boy will eventually reach at the end of growth period.

Name two plant organ which is responsible for:
Absorption if water and minerals.

How does a sound making object differ from one that is silent?

Which type of friction comes into play when a book kept on cylindrical pencils is moved by pushing?

The use of excessive fertilizers in the fields lead to the deficiency of an important substance in the water of a nearby lake. Name the substance.