Answer:
Oxidation is defined as the chemical process in which substance loses electron and hydrogen or gain oxygen while in the process of reduction, substance gains electron and hydrogen or loses oxygen.
So, from the given equation:
a. It is an oxidation reaction as Rb loses one elctron.
b. It is a reduction reaction as Te gains two electrons and become Te2-
c. It is a reduction reaction as H atom gains electrons.
d. It is an oxidation reaction as P loses 3 electrons.
In this kind of exercises, you should use the "ideal gas" rules: PV = nRT
P should be in Pascal:
445mmHg = 59328Pa
1225mmHg = 163319Pa
V should be in cubic meter:
16L = 0.016 m3
R =

= constant

=

==> P1 * V1 = P2 * V2
V2 =

=
V2 = 0.00581 m3 = 5.81 L
The hardest material is diamond. The hardest artificial substance would wurtzite boron nitride. That's basically just man-made diamonds.
Endocrine system im pretty sure
It would weigh 6.77 kilo i believe