Answer:
C. A concentration gradient must exist.
Answer: Food webs are bigger, food chain is smaller.
Explanation:
Food webs are multiple food chains into one web.
Answer:
It could require the removal of massive amounts of top soil, leading to erosion, loss of habitat and pollution.
Explanation:
Coal mining causes acid mine drainage, which causes heavy metals to dissolve and seep into ground and surface water.
Answer:
In meiosis I, crossing over during prophase and independent assortment during anaphase creates sets of chromosomes with new combinations of alleles. Genetic variation is also introduced by random fertilization of the gametes produced by meiosis.
Explanation:
The pairing of homologues at the beginning of meiosis I ensures that each gamete receives one member of each pair. The pairing of homologues brings together the near-identical sequences found on each chromosome, and this sets the stage for crossing over.Following crossing over, at least two of the four chromatids become unique, unlike those of the parent.The frequency of recombination is not uniform throughout the genome. Some areas of some chromosomes have increased rates of recombination, while others have reduced rates of recombination . Recombination or crossing over occurs during prophase I. Homologous chromosomes – 1 inherited from each parent – pair along their lengths, gene by gene. Breaks occur along the chromosomes, and they rejoin, trading some of their genes. The chromosomes now have genes in a unique combination.Independent assortment is the process where the chromosomes move randomly to separate poles during meiosis. A gamete will end up with 23 chromosomes after meiosis, but independent assortment means that each gamete will have 1 of many different combinations of chromosomes.
This reshuffling of genes into unique combinations increases the genetic variation Slightly different sequences in the genetic code of different individuals from the same species. This is important for species adaptation to occur in a population and explains the variation we see between siblings with the same parents.
Explanation:
These mutations can either be inherited or spontaneous. When mitochondria stop functioning, the cell they are in is starved of energy. So, depending on the type of cell, symptoms can vary widely. As a general rule, cells that need the largest amounts of energy, such as heart muscle cells and nerves, are affected the most by faulty mitochondria.
