FeS is an example of an ionic compound as in the formula there is a metal of Fe iron chemically bonded to the nonmetal S sulphur. Resulting in a strong electrostatic attraction due to the transfer of valence electrons from the iron to the Sulphur.
Answer:
D. the organism is able to survive and reproduce more than others in it's environment
Explanation:
It will only go extinct if it can't survive or reproduce.
Answer:
Density, 
Explanation:
The attached figure shows a 38.6 kg marble slab. The dimensions of the marble slab is 23 cm × 17 cm × 4 cm
Density = mass/volume
Volume of a cuboid shape is equal to, V = 23 cm × 17 cm × 4 cm
V = 1564 cm³
Density,

or

So, the density of the marble slab is
.
Cobalt is a Transition Element and it has a partially filled d-orbital. As given it has atomic number 27. In neutral state Cobalt has 27 electrons. These electrons are filled in following order,
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁷
Or it can also be written as,
[Ar] 4s², 3d⁷
Where; [Ar] is Argon with electronic configuration 1s², 2s², 2p⁶, 3s², 3p⁶.