If relatively small carbonaceous chondrites from space were a significant source of Earthʹs original amino acids, then which two of these would have been most important in permitting their organic materials to survive impact with Earth?

I. Carbonaceous chondrites must contain no D-amino acids.

II. Earthʹs early atmosphere must have had little free oxygen.

III. The chondrites must have arrived on Earth before 4.2 billion years ago.

IV. Earthʹs early atmosphere must have been dense enough to dramatically slow the chondrites before they impacted.

V. The chondrites must have impacted land, rather than a large body of water.

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#Question id: 4165

#SCPH06 I Botany

Which is true about proofreading activity during the synthesis of aminoacyl-tRNAs?

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#Question id: 4732

#SCPH12 I Genetics

What is F2 phenotype ratio observed when a homozygous recessive mutation in either or both of two different genes results in the same mutant phenotype?

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#Question id: 4565

#SCPH06 I Botany

Darwinʹs mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earthʹs ancient age?

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#Question id: 15910

#SCPH05 I Biotechnology

In HMM, transition probability is describes as 

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#Question id: 5543

#SCPH01 Biochemistry

What is the purpose of the chorion in terrestrial vertebrate embryos?