Lternative splicing can process the same pre-mrna into different forms of mrna. which one of the following reasons best explains why this pre-mrna can't be processed into a mrna containing only (exon 1-intron a-exon 3)?
a. the spliceosome can not excise rna sequences bounded by two 5' splice sites.
b. the spliceosome can not excise rna sequences bounded by two 3' splice sites.
c. the spliceosome can not excise rna sequences bounded by an upstream 5' splice site and a downstream 3' splice site.
d. the spliceosome can not excise rna sequences bounded by an upstream 3' splice site and a downstream 5' splice site.

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !

the answer is c most of the fortnite players usually buy v bucks to get the battle pass and other cosmetics but some players who are referred to as "no skins" don't   buy skins and are usually noobs.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

digestion

it excretes wastes