Question

1. erve impulse moves along a neuron as

   	A.	sodium moves into the cell and potassium moves out of the cell.
   	B.	sodium binds to potassium.
   	C.	sodium and potassium are pulled apart.
   	D.	acetylcholine moves along the nerve fiber.
   	E.	calcium exits the dendrites.

1 points

Question 57

1. How might climate change effect the reproductive success of organisms?

   	A.	Changes in the length of seasons.
   	B.	Changes in seasonal temperature.
   	C.	There will not be much of an effect.
   	D.	A and C.
   	E.	Both A and B.

1 points

Question 58

1. Biological diversity may be protected by which of the following activities?

   	A.	limiting destruction and fragmentation of natural habitat
   	B.	removal of non-native, invasive species
   	C.	guarding against illegal commercial hunting and harvest
   	D.	protection of endangered species, especially keystone species
   	E.	All of the above are good ideas when considering conservation of biodiversity.

1 points

Question 59

1. Why is it important for muscles to have some sort of antagonistic opposition such as another muscle, differential air pressure, or elastic tissue?

   	A.	Because muscles can only push, not pull.
   	B.	Competition leads to quality products and lower prices.
   	C.	Because contraction depletes the muscle’s ATP stores, and it needs help from another muscle to re-fill itself with energy carrying electrolytes.
   	D.	Muscles may only forcibly contract.
   	E.	Information in the nervous system only flows in one direction, so a different neuron must signal the muscle to extend than the one that signals it to contract.

Answer 1

Answer 56:

Option A - Sodium moves into the cell and potassium moves out of the cell
Ion channels maintain the electrical potential within a neuron. After an influx (moving in) of Sodium causes the neuron's membrane potential to exceed it's threshold, a nerve impulse sends an electrical signal down the axon.

Answer 57:

Option E - both options A & B
  A- Changes in the length of season
B- Changes in seasonal temperature
Organisms are dependent upon many things in nature for their reproductive successes. One of the Factors in climate. Climate change either alters their reproductive behaviour. Some organisms are very sensitive to temperature and will not reproduce until they feel that offspring will be given utmost survival chance.

Answer 58:

Option E- All of the above are good ideas when considering conservation of biodiversity.
In order to conserve biodiversity, destruction of natural habitat must be stopped, the non-native invasive species that give competition to the native flora and fauna should be removed, illegal hunting and harvesting of jungles should be guarded against and endangered species must be protected.

Answer 59:

Option D- Muscles may only forcibly contract.
Muscles work to move the bones. They always work in pairs called antagonistic pairs. When one muscle contracts to bend the joint in one direction, the other simultaneously relaxes. The second muscle works to move the bone to it's original position.