Yukti Sharma Solutions for Exercise 1: February 2016

All of the following are single-celled, except:

Read the following examples from daily life and select the appropriate option:

I. When food gets spoiled, it produces a foul smell.
II. A slice of apple acquires brown colour when kept out for some time.
III. When an ant bites, calamine is used to ease the irritation on the skin.

A student burns a magnesium ribbon in air and dissolves the ash of the ribbon left after burning in distilled water. On pouring one drop each of this solution, first in blue litmus and then in red litmus solution, he would observe that:

'Copper cannot displace zinc from it salt solution'. Give the reason. The following reasons are given by Class VIII students:

I. Copper is more reactive than zinc.
II. Copper is less reactive than zinc.
III. Zinc is one of the noble metals.
IV. Zinc appears below copper in reactivity series.

Select the correct reason(s) from the reasons given by Class VIII students.

Select from the following a group of diseases caused by bacteria.

Consider the following Column-A and Column-B in which the names of microorganisms are given in Column-A and the groups to which they belong are given in Column-B:

The correct match of the terms Column-A with that of Column-B is:

Which of the following statements are true about veins in the human circulatory system?

I. All veins carry carbon dioxide-rich blood.

II. Veins have thin walls.

III. Veins carry blood from different organs to the heart.

A book is lying at rest on the surface of a table. Which one of the following statements is true about the force(s) acting on it?