Answer:
In eukaryotes, the genome comprises several double-stranded, linear DNA molecules bound with proteins to form complexes called chromosomes
Answer:
The order of events would be:
4.Threshold stimulus, Na+ channels open. This is the first event
5.Na+ influx, Depolarization. Second event
2.Na+ channels close, K+ channels open. This is the third event
1.K+ efflux, Repolarization. Fourth event
3.Hyperpolarization, K+ channels close
Explanation:
In resting state, the membrane is negative inside, and K+ concentration is higher than outside. Na+ concentration is higher outside instead.
Sodium influx is responsible for membrane depolarization. It's the event to produce the action potential. When sodium channels are closing, potassium channels open and K+ go outside until repolarization occurs. But now we have both ions in different sides of the membrane, and this can't be stimulated again to produce other action potential. The membrane will remain refractory to respond to the adequate stimulus until ions migrate to their original sites. This is Na+ outside, and K+ inside. This is responsibility of the Na+/ K+ pump, that uses ATP to pump Na+ out, and K+ in. Once both ions had been relocated in the membrane, this is ready to receive a correct stimulus to produce a new action potential.
Explanation:
Many invertebrate animals cant survive in water that has been polluted and resulted in a lowering of oxygen concentration so the presence or absence indicates the extent to which a body of water is polluted.
Lichens can be used to indicate air pollution as they grow exposed to places such us rocks and tree barks. They need to be efficient at absorbing water and nutrients to grow there. Rain water contains enough nutrients to keep them alive. Air pollutants dissolve in rain water especially sulfur dioxide can damage lichens and prevent them from growing. This makes them a natural indicator of air pollution.
