The correct answer is option (d) that is dizygotic twins.
The dizygotic twins also known as non-identical twins or fraternal twins, that is, two siblings who come from distinct eggs or ova, which are discharged at the similar time from an ovary and are fertilized by different sperm.
Answer:
A threshold level depolarization.
Explanation:
In a neuron, the action potential threshold is known as the point of depolarization where the neuron fires, when the neuron reaches a point, it will fire and if it does not reach the point of depolarization, it will not fire and it helps to transmit the information to another neuron.
A neuron transmits the information with the help of electric impulses which are sent through its axon. When a neuron in an inactive phase, more +ve charged ions recline outside the axon membrane. In the process of stimulation, the axon membrane admits more Na+ ions and providing the neuron more +ve charge.
The nail breathes oxygen to live. The nail breathes the oxygen dissolved in the water.
Given that the aquarium is a small bioma there is not enoguh source of oxygen to replace the oxygen consumed by the snail, except for the oxygen produced by the aquatinc plants inside the aquarium.
Plants produce oxygen through the process named photosynthesis. Photosynthesis requires light.
Given that the aquarium is kept dark, the aquatic plants cannot carry out the process of photosyntthesis and so there will not be generation new oxygen and the snails will die after they do not have oxygen to breath.
I
