Because natural selection is caused so that an organism can adapt and better survive their environment. They are involved in the formation of fossils because organisms that die are buried in sediment and become fossils.
Explanation:
a sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.
Answer:
<u>Sister chromatids are identical forms of chromatids of a chromosomes. They are mostly formed by semi-conservative replication of DNA molecule of a single chromosome.Thus they are like </u><u>'photocopies' </u><u> of original parent chromosomes; joined together at the Centromere</u>.
They are exactly similar in all ramification; with the same gene and allele compositions..
<u>However; slight differences arise between the two identical sisters due to </u><u>mutation</u><u> from</u><u> errors </u><u>at replication;and also in the length of telomere repeats.</u>
Non-sister chromatids are dissimilar forms of chromatids of a chromosomes formed when each half of a chromosome at fertilisation from separate haploid sex-cells, of each parent. fused.They contain different genetic composition;because they are not on the same homologous chromosomes.Therefore crossing -over ensure variation.
<u>However, they are genetically similar in composition; if they are contained in homologous chromosomes</u>. This is because Synapsis of bivalent of these chromosomes allow genetic material to be shared by chromosomal crossing-over between the non-sister chromatids on the chromosomes ; therefore identical genetic characteristics are shared .
Explanation:
Answer:
1. Earth's ozone layer is responsible for absorbing infrared and ultraviolet rays from the sun.
2. Changes in the composition of the atmosphere have caused gradual changes in earth's climate, causing changes in plant and animal life that contributed to mass extinctions.
3. Chemical chlorofluorocarbons (CFCs) have been banned and replaced with hydrochlorofluorocarbons (HCFCs).
4. Naturally occurring volcanic eruptions can produce large amounts of gases which contain sulfur. These gases accumulate in the atmosphere in the same way as man-made sulphuroxides.
Sorry, but after that I don't know.
Explanation:
Answer:
The molecules that bind cellular respiration enzymes act as signals, giving the enzyme information about the cell's energy state. ATP and ADP are examples of molecules that regulate cellular respiration enzymes. ATP, for instance, is a "stop" signal: high levels mean that the cell has enough ATP and does not need to make more through cellular respiration.
This is a case of feedback inhibition in which a product feeds back to shut down its pathways.