1. Cenozoic ERA
2. Mesozoic ERA
3. Paleozoic ERA
Answer:

Explanation:
Since the universal SI unit for velocity is meters/second, let's convert ft/s to m/s:

We can use the following kinematics equation to solve this question:

What we know:
- The initial velocity,
, is
- (physics concept) The final velocity must be equal in magnitude but opposite in direction to the initial velocity (
) - Acceleration,
, is acceleration due to gravity at about
Solving for
:

Answer:
1.11×10⁸ Electrons.
Explanation:
Applying,
Q = CV..................... Equation 1
Where Q = Total charge on the capacitor, C = Capacitance of the capacitor, V = Voltage of the battery.
Given: C = 1.97 pF = 1.97×10⁻¹² F, V = 9.0 V
Substitute this value into equation 1
Q = 1.97×9×10⁻¹²
Q = 1.773×10⁻¹¹ C.
If the charge on one electron = 1.602×10⁻¹⁹ C.
Therefore number of electron = 1.773×10⁻¹¹ /1.602×10⁻¹⁹
Number of electron = 1.11×10⁸
115.94g of O₂ are produced by 250g of Ca(ClO₃)₂
<u>Explanation:</u>
Ca(ClO₃)₂ -->CaCl₂ + 3O₂
One mole of calcium chlorate give three moles of oxygen.
Molar mass of calcium chlorate is
40+(35.5+16*3)*2 = 207g/mol
Molar mass of Oxygen = 32g
1 mole of calcium chlorate decomposes to form 3 moles of oxygen.
So,
207g of Ca(ClO₃)₂ produces 3 X 32g of O₂
250g of Ca(ClO₃)₂ will produce = 
= 115.94g of O₂
Therefore, 115.94g of O₂ are produced by 250g of Ca(ClO₃)₂