The organisms which appeared on earth first was bacteria.
<u>Explanation:</u>
- The first-ever living organism on Earth was a bacteria known as cyanobacteria. It is believed by scientists that it first formed around 3 billion years ago.
- When the Earth was first formed, it was inhospitable for a long time until 3.8 billion years ago approximately, the core cooled down and the level of oxygen had risen. This, along with photosynthesis resulted in the formation of Cyanobacteria.
- These organisms were capable of carrying out the process of photosynthesis by which they prepared their food. These were known as common ancestors. All the living organisms thereafter are known to be their descendants.
Answer:
when the size of a star increases, luminosity of star also increases.
The color of a star is decided by the surface temperature of the star and the temperature of a star depends on the size of star.
The smaller stars have low temperature and they are usually red (Proxima Centauri - red dwarf star).
The massive stars have higher temperature and they are usually blue (for exaple Zeta Puppis - Blue supergiant star).
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Explanation:
It should be based on the principles of immunology to understand this phenomenon: the immune system produces antibodies against an antigen that it does not possess
The AB group contains the A and B antigens on the red blood cells, so it can not produce anti-A antibodies or anti-B antibodies since it already possesses antigen A and B (otherwise it will develop autoimmunity).
Answer:
The tongue is covered with around 9,000 taste buds that are replaced every 10 days.