Answer:
Momentum, 
Explanation:
Given that,
Mass of a mosquito, m = 0.000015 kg
Velocity of the mosquito, v = 5.2 m/s
We need to find the momentum of the mosquito. The momentum of an object is given by :
p = mv
Put all the values in the above formula.

So, the momentum of the mosquito is
.
An isotope is one of the forms of an element that has the same number of protons, but a different number of neutrons.
Answer: A) highly mobile electrons in the valence shell
Explanation: conductivity in metals is a result of the movement of electrically charged particles—the electrons. These free electrons also known as valence electrons are free to move, and as a result they can travel through the lattice that forms the physical structure of a metal. The presence of valence electrons determines a metal's conductivity. However, several other factors can affect the conductivity of a metal such as impurities, temperature, magnetic fields etc.
Efficiency = (Wanted) energy out ÷ energy in × 100
Energy in = 400J
Wanted Energy out = 240J
Energy cannot be used up, only transferred, so the remaining energy is most likely to be transferred into unwanted energy (loss of energy) such as heat energy.
Efficiency = 240 ÷ 400 × 100
Efficiency = 0.6 × 100
Efficiency = 60%
The era that dinosaurs came was in the Mesozoic Era!