The question is incomplete. The complete question is attached below.
Answer:
1. DNA is the polymer of deoxyribonucleotides that contain the nitrogenous base, pentose sugar and phosphate group. The phosphate is attached with the 3 C position of the deoxyribose sugar. This leads to teh formation of phosphodiester bond.
2. The DNA backbone consists of phosphate and sugar. The nitrogenous bases are inserted inside the DNA molecule. These nitrogenous bases are linked together by the hydrogen bonds.
3. The adenine binds requires two hydrogen bonds to bind with thymine. This provide complementary nature to the DNA molecule. Uracil is present instead of thymine in RNA .
4. The guanine binds requires three hydrogen bonds to bind with cytosine. More amount of energy is required to break their bonds.
Answer:
A. The heartbeat can be heard
Explanation:
After the first trimester, during the fourth month, the heartbeat of the fetus becomes loud enough to be heard with the help of a stethoscope placed on the abdomen of the mother.
From fifth to the seventh month of the development, kicks and jabs are felt by the mother as the fetal legs grow and develops. Languo, a wrinkled pink colored skin covers the fetus.
Languo is in turn covered with a white greasy substance called vernix caseosa.
From eighth to ninth months, rotation of the fetus places its head pointing towards the cervix to facilitate childbirth later.
The development of testes takes place in the seventh month while the body hairs become disappeared in the eighth month.
Answer:
A. The new evidence could be accepted and the theory changed.
Explanation:
most reasonable answer
I believe it is behavioural isolation. When there are changes within a certain species, e.g. new birdcalls are formed in certain individuals in a species, "traditional" birds may not like such mating calls and only choose to mate with the more common birdcalls from majority of the birds. There are also some birds that may like the new birdcalls, and choose to mate with birds with those birdcalls. They become genetically isolated as they continue such behavior. Eventually, through genetic drift and other mutations, different species form from a single specie.
Hope this helps! :)