Answer:

Explanation:
Step 1. Calculate the pOH
pOH =-log[OH⁻]
pOH =-log(1.0 × 10⁻⁹)
pOH = 9.00
Step 2. Calculate the pH
pH + pOH = 14.00
pH + 9.00 = 14.00

Mendeleev left gaps in the periodic table because, in the future, he knew that there would be more elements to be discovered because not all elements were discovered at the time.
Answer:
Respiration process
Explanation:
Respiration is simply defined as the biochemical process where the body cells derive their energy from the combination of O₂ and food molecules, and in return liberates CO₂, along with some amount of H₂O and energy. This process elaborates on how the tissue cells help in shifting the O₂ from the exterior air into the cells and in return allows the CO₂ to be released outside.
This process is highly essential for an organism to survive. An organism cannot survive without carrying out this process.