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!
Answer: If a mutation occurred in Silencer of Death Domain (SODD) that prohibited its interaction with the DD of TNF receptor, the TNF receptor would evoke its response by binding to a transmembrane receptor, TNFR1.
Explanation: Binding to TNFR1 inhibits the recruitment of cytoplasmic signaling proteins to TNFR1 to prevent recruitment of a number of protein (TRADD) or prevent spontaneous aggregation of the cytoplasmic death domains of TNFR1 molecules.
SODD mechanism is useful in preventing unwarranted TNFR1 activation in the process of apoptosis.
The answer is the first one: “...attract each other.”
Chickens have 78 chromosomes.