Number of neutrons = mass number - atomic number = 40 - 19 = 21 answer
The dermal tissue is basically the outer part of the cell that protects the plant cell so in that case it would be the carbohydrate or cell wall. If you would put the choices it could have been a bit better :)
Answer:
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment, in which he demonstrated that the atom has a tiny, high- mass nucleus. In his experiment, Rutherford observed that many alpha particles were deflected at small angles while others were reflected back to the alpha source.
Answer:
a rapidly flowing river discharges into the ocean where tidal currents are weak.
Explanation:
The force of the river pushing fresh water out to sea rather than tidal currents transporting seawater upstream determines the water circulation in these estuaries.