The earth is a unique planet in that it is covered by more than 70 percent water. there are several properties of water that make earth a suitable environment for life, including how the density of solid water (ice) is about nine percent less than the density of liquid water. which best explains why this feature of water is important for marine life?
ice forms from the bottom of the water column up, allowing organisms to freeze and enter hibernation.
ice forms from the top of the water column down, creating a protective barrier over the liquid water.
the higher-density liquid water shelters organisms from cold air better than the less-dense ice.
the higher-density liquid water traps nutrients for primary producers better than the less-dense ice.
scientists have been studying threats to coral reefs. some reefs around the southeast shore of australia have experienced increased threats while others in the northwest shore of australia have seen a decrease in threat. explain the most effective way that scientists could use this information to design a new study aimed at developing reef protections.
scientists could compare environmental conditions in the threatened australian reefs with other reefs near florida, since there would be little overlap in their characteristics.
scientists could compare environmental conditions in the two sets of australian reefs, because those reefs are more likely to be similar in many ways. this will highlight the difference that is causing the threat.
scientists could compare environmental conditions in two sets of reefs in florida and apply that data to the reefs in australia.
scientists could compare environmental conditions in reefs randomly selected from around the world to get the most variable set of conditions possible and to make good comparisons.

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.

transcription is a process in which information is rewritten. it is something our cells must do, in a more specialized and narrowly defined way. in biology, transcription is the process of copying out the dna sequence of a gene in the similar alphabet of rna. it needs to happen in the nucleus because that's where the dna is. dna is always inside the nucleus unless the cell is dividing.

transcription is the first step in gene expression, which involves copying a gene's dna sequence to make an rna molecule. transcription is performed by rna polymerases. it has three stages: initiation, elongation, and termination. rna molecules must be processed after transcription in eukaryotes.

explanation:

long version:

the protein synthesis consists two processes which are, transcription and translation. transcription takes place in the nucleus. it uses dna as a template to make an rna molecule. rna then leaves the nucleus and goes to a ribosome in the cytoplasm, where translation occurs. transcription is the first part of the central dogma of molecular biology: dna → rna. it is the transfer of genetic instructions in dna to messenger rna (mrna). during transcription, a strand of mrna is made that is complementary to a strand of dna.  

these three stages are:

  initiation: in which   is the beginning of transcription.occuring when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

    elongation: in which is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

    termination: in which is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

succession returns a disturbed

ecosystem to a more stable state. this is also classified into two (2) types:

primary succession and secondary succession. the primary succession arises when

a new land is transformed and a bare rock has been exposed providing an environment

that can be occupied for the first time. while, secondary succession occurs

when a previously occupied environment was disturbed that kills much of all its

community

explanation: