Another name for these two words is "constant" and you want to have a "constant", because you want something to compare your experimental group to, to see whether data had changed or not. So you have placebos or a double- blind to compare your experimental group to it and also so you know you don't have a bias or anything in the study.
A 5kg backpack will weigh 49 newtons on earth
Answer:
No sand doesn't stay sand forever.
Explanation:
- We may have a thought that the sand we see on the beach areas are always the same one for eternal, but it is not true.
- Due to different activities like beach nourishment, sand replenishment etc. the sand in the beach areas are changed and replaced.
- If the sand remained there for long time, it also affects the sand eating organisms and plants.
2 near the middle
between ultraviolet and infared
