Answer:
We don't know.
Explanation:
We need more to answer this.
Hi
It is true that on the Galapagos islands Darwin observed tortoises with a dome and saddle shaped shells, you can see both in attached image.
Darwin observed that Galapagos Tortoises had the shells with different shapes depending on the Island they live, For example: The tortoises with saddle shaped shells were able to reach up to eat leaves of plants while the tortoises with dome shaped shells would not reach up and they would eat food from on ground sources. This made him think that the differences in tortoise shell is also a strong evidence that indicates that how tortoises have adapted themselves to better get their food as per the available resources and how they have evolved from same ancestral specie into two different species. This point also helped him in proposing the theory of evolution by natural selection.
Hope it helps!
The base which is Uracil or Thymeine
If a substance is very sour and has a ph of 4, then you would expect the litmus paper to turn into the shade of red. A substance that is sour and has a pH level that is below 7 would indicate that the substance is an acid or has acidic properties. For an acidic solution, the litmus would be red in color. If a blue litmus paper is used, then it would turn into red while if a red litmus paper is used, then it would remain as red. There is also a general type of litmus paper where the color change range from violet to red. A litmus is widely used in distinguishing acid and bases. It can be used in liquid solutions and in gas mixtures. <span />
The heart’s electrical system is responsible for making and conducting signals that trigger the heart to beat. These signals cause the heart’s muscle to contract. With each contraction, blood is pumped throughout the body. This happens 24/7 without us having to monitor it all the time so that our heart does not stop.