<span>B. wearing goggles when working with chemicals. Hope this helps :)</span>
<h2>Answer:</h2>
The correct option is B which is micropyle.
<h3>Explanation:</h3>
- Generally micropyle is known as the opening in the ovule or egg from which sperm enters the egg.
- But at the time of germination it is used to absorb water and nutrients.
- It is the micropyle from which the root emerges from the seed.
<u>Answer:</u>
Cyanobacteria start producing pure oxygen around 200 million years ago.
<u>Explanation:</u>
Many scientists believed that Earth did not have any oxygen. Cyanobacteria or the blue green algae are the microbes which produced oxygen for the first time with the help of photosynthesis. This was around 4.5 billion years ago: after Hadean eon.
They were very simple, but they produced oxygen in the early earth’s atmosphere. So, they brought evolution on earth. This “blue-green algae” exists in salt water, rocks and soils and play a major role in maintaining the ecosystem.
C. alive. The vaccine contains a live strain of varicella-zoster (chicken pox) virus which has been attenuated so that it will stimulates the immune system but does not cause any disease in healthy people.
