Because there is only a finite amount of energy. Energy is lost between each trophic stage. The top predator would gain the least amount of energy, shared between the least amount of organisms within the predator species. Typically there just aren't any other animals that can kill and eat the top predator, but there also wouldn't be enough of the top predator to eat so any species above them would quickly die out.
B.) Adenine because Dictated by specific hydrogen bonding patterns, Watson-Crick base pairs (guanine-cytosine and adenine-thymine) allow the DNA helix to maintain a regular helical structure that is subtly dependent on its nucleotide sequence.
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Answer:
D. The virus uses the host cell to make new viral parts.
Explanation:
The virus is an organism that is incapable of replicating on its own without a living host cell. It needs to infect a living cell in order to reproduce. The infection cycle of a virus is the replication cycle. Viruses employ two major infection cycles: LYTIC or LYSOGENIC cycles.
In the lytic cycle, the virus initially attaches to specific receptor sites on the host cell membrane. It then penetrates the host cell and incorporate its genetic material into the host cell's genome. It employs the host's ability to express its genes and replicate to express its genes and make new proteins. At the end of the LYTIC cycle, new viral particles (virions) are produced and released by lysis of the host cell.
During the S phase hope that helped
