Celsius scale is related to kelvin scale by the following equation,
⁰C = K-273
°C = K-273
So as here temperature is given in kelvin, so it can be converted into celsius as follows:
So 20 K = 20K-273 °C
= -253 °C .
So, the 20 K temperature equals to -253 °C.
So , -253 °C is equals to 20 K or 20 K temperature equals to -253 °C.
Answer:

Explanation:
Hello,
In this case, for the given chemical reaction, we first identify the limiting reactant by noticing that due to the 1:1 mole ratio for magnesium to iodine the reacting moles must the same, nevertheless, there are only 2.68 moles of magnesium versus 3.56 moles of iodine, for that reason, magnesium is the limiting reactant, so the theoretical turns out:

Thus, we compute the percent yield as:

Best regards.
Answer:
A) in response to an increase in the cytoplasmic Ca2+concentration.
Explanation:
Muscle contraction occurs in response to an increase in the cytoplasmic Ca2 + concentration.
This process occurs with the shortening of the sarcomeres resulting in a result, the actin filaments react with myosin, generating actomyosin. During this reaction, it is necessary to increase the cytoplasmic concentration of Ca + and ATP. In this, myosin will break down ATP, releasing energy so that the muscle can contract.
Valence elections, electron affinity, electronegativity, atomic radius
The general properties of Group 1 alkali metals are:
1. They form cations.
2. They are highly reactive.
3. They have a charge of +1.
4. They form ionic compounds.
5. When their oxides or hydroxides are reacted in water, they form alkalis i.e. bases.
6. They are usually soft in nature.
7. They have low densities.