I think it is B. biome
Because biome means a large area dominated by characteristic plants and animals, such as a rain forest, desert, or tundra.
Carbon Monoxide has 2 atoms total - one atom of carbon (C) and one atom of oxygen (O) chemical formula is CO
Ethylene has 6 atoms total, 2 atoms of carbon (C) and 4 atoms of hydrogen (H), chemical formula is C2H4.
Ethylene has four more atoms than carbon monoxide (6-2) = 4
Flower because the others are a organ which make the plant live but the flower is more of a decorative thing to make the plant stand out
Answer:

Explanation:
We recognize that total occurrence equals new cases of disease over time divided by the number of people at risk at the onset.
Mathematically:

Given that:
Number of the population at risk = 1000 individuals
New cases during Jan 1 - Dec 31 = 60 because;
At 20 occurred on June 30 & 40 on Sept. 30) & no new cases were identified after that:
∴
