Answer:
changing environment
Explanation:
If the species fails to adapt, it will die off.
Answer:
One strand of all the isolated DNA double helices would have C-14 labeled thymidine.
Explanation:
DNA replication is a semiconservative process which means that each newly formed DNA double helix contains one parental strand and one newly formed strand.
Since the medium has thymidine labeled with C-14, all the newly formed strands formed during DNA replication would have radio-labeled thymidine.
Therefore, by the end of 20 minutes, one out of two strands on each double helix would have labeled thymidine nucleotides.
Natural Selection helps animals survive in their habitats and they have adaptations to help them survive better.
Answer:
cardiac
Explanation:
An electrical stimulus is generated by the sinus node (also called the sinoatrial node, or SA node). This is a small mass of specialized tissue located in the right upper chamber (atria) of the heart. The sinus node generates an electrical stimulus regularly, 60 to 100 times per minute under normal conditions.