Structure of the Atom — Science STD 9 — Question

In a sample of ethyl ethanoate (CH₃COOC₂H₅) the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?

Plant cell wall mainly consists of:

Actively dividing tissues are:

Pollution of water is caused by:

1. Industrial effluents.
2. Sewage.
3. Farm runoff.
4. All of these.

A freely falling object travels 4.9m in 1st second, 14.7m in 2nd second, 24.5m in 3rd second, and so on. This data shows that the motion of a freely falling object is a case of:

Which of the following actions can be grouped as pull: Moving a loaded cart. Applying brakes while driving car. Drawing a bucket of water from a well

Among the following, name a mixture which is used as a food:

Aleuroplasts in a cell store:

1. Starch.
2. Oil.
3. Protein.
4. Nutrients.

Which are not true cells in the blood?

1. Platelets.
2. Monocytes.
3. Basophils.
4. eutrophils.