Answer:
Explanation:
Dna is shaped as a double helix and has weak hydrogen bonds. They contain complementary base pairs (adenine and thymine) and (guanine and cytosine).
Hope this helps.
Answer: too make you have more and more screen time.
Explanation:
The answer is d. Source water are River, streams, lake etc that provide drinking water
Explanation:
As Earth cooled, an atmosphere formed mainly from gases spewed from volcanoes. It included hydrogen sulfide, methane, and ten to 200 times as much carbon dioxide as today's atmosphere. After about half a billion years, Earth's surface cooled and solidified enough for water to collect on it.
Oxygen plays a critical role in respiration, the energy-producing chemistry that drives the metabolisms of most living things. We humans, along with many other creatures, need oxygen in the air we breathe to stay alive. Oxygen is generated during photosynthesis by plants and many types of microbes.
Answer:
The correct answer is spirochete and cyanobacteria
Explanation:
The endosymbiotic theory states that the eukaryotic cells are evolved from prokaryotic cells when a larger prokaryotic cell engulfed the smaller prokaryotic cell. The presence of chloroplast and mitochondria supports this theory.
After genetic analysis of chloroplast DNA, it was seen that it closely resembles the cyanobacterial DNA which shows that ancestor host cell gained photosynthetic ability from endosymbiosis with a cyanobacterial ancestor.
It was also seen that ancestral host cells engulfed spiral bacteria called spirochetes which helped them to produce cilia for example tail on sperms is the result of endosymbiosis of spirochete. So the right answer is spirochete and cyanobacteria.
