Tissues — Science STD 9 — Question

Onion peel is used to demonstrate:

The frequencies of four sound waves are given below. Which of these sound waves can be used to measure the depth of sea by the echo method?

The conversion of NO₃ to N₂ is called:

1. Nitrification.
2. Denitrification.
3. ammonification.
4. Nitrogen fixation.

The meristerm which develops into primary vascular tissue is:

Which of the following is not a longitudinal wave?

A truck covers 40km with an average speed of 80m/h. then it travels an average speed of 40km/h. the average speed of the truck for the total distanced covered is:

In case of negative work, the angle between the force and displacement is:

Rinku and Pinku had half day schools during summer. They used to go to school by autorickshaw. They observed that the auto driver covered the top of the vehicle by some mats and sprinkled water on them regularly, which keeps it cool. Which of the following phenomena is involved here:

Animal cell lacking nuclei would also lack in:

Rabi crop is: