B. He was the first person to observe and identify living cells.
Answer:

Explanation:
The hydrocarbon shown has a double bond. Hydrocarbons with double bonds are known as alkenes.
Cyclic alkanes have cyclic structure.
Alkanes only have single bonds.
Alkynes have triple bonds.
Q = mcΔθ
67.5 = m x 0.45 x (28.5 - 21.5)
M = 67.5 / 3.15
= 21.4 g
The serving of peanut butter contains 117kcal
<h3>Calculation of calories of food Nutrients</h3>
1 gram of both carbohydrate and protein contains 4 (kcal)
1 gram of fat contains 9 (kcal)
But peanut butter contains 5g of fat. The kilocalories of fat present is;
1 g = 9 kcal
5g = F
F = 5×9
F = 45 kcal
The kilocalories of carbohydrates present is;
1g = 4kcal
12g = C
C= 12×4
C = 48kcal
The kilocalories of proteins present is;
1g = 4kcal
6 g = P
P = 4× 6
P = 24 kcal
Therefore, the total kilocalories of the peanut = 45 + 48 + 24 = 117kcal
Learn more about kilocalories here:
brainly.com/question/6423812