This is formed as a waste product in photosynthesis and used as a reactant in respiration.

Oxygen

Explanation:

Photosynthesis is a process performed by the plants (also some algae and bacteria) in which the energy of sunlight is transformed into chemical energy usable by those plants. Necessary components of this set of reactions are sunlight, water and CO2, while resulting products are glucose and oxygen. Products of photosynthesis are then used in the metabolic processes known as cellular respiration. During the cellular respiration, glucose and oxygen are used for the production of ATP, CO2 and water. Cellular respiration is performed in all living organisms.

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.