The correct answer is (b.) an increase in the width of the stem. The increase in the width of the stem could be referred to as the secondary growth of the stem. Whereas the primary growth is the upward growth of the plant.
Answer:
The correct answer would be - "bacterial populations evolve in response to the selection pressure imposed by antibiotics".
Explanation:
The given information provided in the question about the bacterial infection supports the hypothesis that the bacterial population shows the evolution in response to the selection pressure caused by the antibiotics due to the fact that bacteria increased resistance gradually with time. This resistance towards antibiotics increased the percentage of bacterially infected children in the late 1980s and early 1990s.
In this case, the population of bacteria having resistance genes is selected to evolved selected to increase their offsprings.
Answer: C
Explanation: Earth's atmosphere isn't very dense because it is made of air, which floats. Human beings are denser then air since they are solid, but not as dense as Earth's crust, which is rocky and the densest out of the three.