Answer: The given statement is True.
The proliferation of photosynthetic planktons results in harmful algal blooms. Due to this, the surface of the water body gets completely covered with algal bloom. This blocks the sunlight as it can not penetrate the water. Due to this, photosynthetic planktons are no more able to perform photosynthesis. This ultimately ends up depleting all oxygen from the body of water.
Thus, the given statement is true.
The earth is considered an Open system which is B.
Answer:
De broglie wavelength will be 0.727 nm
Explanation:
We have given speed of the electron 
Mass of the electron 
Plank's constant 
We have to find the De Broglie wavelength
De Broglie wavelength is given by 
So wavelength will be 0.727 nm
When all atoms that make up a substance are the same, then that substance is an element. Elements are made of only one kind of atom. Because of this, elements are called "pure"
