<span>For calcium to be absorbed it must bind to a hormone regulated brush border protein called Calbindin.
Calbindins are calcium binding protein. As it names also shows that, Cal for calcium and bindin for binding. they are also described as vitamin D dependent calbindin proteins.
Calbindin-D9k and Calbindin-D28k are two identified forms of protein. </span>
Answer:
The missing step is oxygen is removed from the water after step 3.
Explanation:
The steps listed by Xavier are:
- <em>Water is drawn in trough pores and enters the central cavity.
</em>
- <em>Food is filtered and digested.
</em>
- <em>Water leaves trough an opening at the top of the body.</em>
Porifera or sponges are aquatic, immobile invertebrates whose structure is saccular with an upper opening, the osculus.
Sponges absorb water through their pores, where the porocytes are found, and through flagellated cells -the coanocytes- the movement that allows the entrance of water to the spongocele or atrium is produced, in addition to the phagocytosis of organic elements.
Once the water is in the interior chamber of the sponges, the organic particles are phagocyted to be digested, and the oxygen is removed from the water, and passes through diffusion into the cell. The waste products, as well as carbon dioxide, are released into the water that will be expelled through the osculus.
<u><em>In Xavier's list, the missing step is the removal of oxygen from the water, before it is expelled from the body of the sponge</em></u><em>.</em>
<em />
Learn more:
Sponge structure brainly.com/question/11256747
Mitochondria are the energy factories of the cells. The energy currency for the work that animals must do is the energy-rich molecule adenosine triphosphate (ATP). The ATP is produced in the mitochondria using energy stored in food. ... This is a very efficient process for using food energy to make ATP.
