I personally thinks it’s A
Answer:

Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
Photosynthesis is the process where plants create energy. It requires water, carbon dioxide and sunlight. The end result is glucose, which the plants consume, and oxygen. Cellular respiration requires oxygen and glucose. The end result is carbon dioxide, ATP, and water.
The alignments of the planets would be the correct answer.<span />
Answer:
K = 0.5
Explanation:
Based on the reaction:
PCl₃ + Cl₂ ⇄ PCl₅
The equilibrium constant, K, is defined as:
K = P PCl₅ / P PCl₃ * P Cl₂
<em>Where P represent the pressure at the equilibrium for each one of the gases involved in the equilibrium.</em>
<em />
As:
P PCl₅ = 1.0atm
P PCl₃ = 1.0atm
P Cl₂ = 2.0atm
K = 1.0atm / 1.0atm * 2.0atm
<h3>K = 0.5</h3>