Answer:
B) Na+
Explanation: Na+ molecule is polar, oxygen and carbon dioxide are nonpolar molecules. The cell membrane is a <em>phospholipid bilayer</em> made up of lipid molecules with polar and nonpolar ends. Since it is a bilayer, two phospholipid layers are arranged, one on the other in such a way that one faces the back of the other. The non polar ends are away from outside and inside of the cell, while the polar ends faces towards all the molecules inside and outside the cell.
Since polar-polar molecules repel each other, Na+ can't pass through the cell membrane easily. So it uses the proteins attached the cell membrane inside and outside to transport such molecules by using energy in terms of ATP.
A baby's immune system is not fully developed until he/she is about six months-old. In the meantime, pregnant mothers pass immunoglobulin antibodies from their bloodstream, through the placenta, and to the fetus. These antibodies are an essential part of the fetus's immune system. They identify and bind to harmful substances, such as bacteria, viruses, and fungi that enter the body. This triggers other immune cells to destroy the foreign substance.
Answer:
Santi is walking barefoot through his yard when he steps on a sharp rock. The skin on the bottom of his foot sends this information through a(n) <em>sensory</em> neuron to his CNS. A(n) <em>interneuron</em> picks up this information and carries it to <em>motor neurons of the CNS</em>, which sends a signal to the muscles in his foot causing his foot to pull away from the rock.
Explanation:
The scenarios discussed in the question is known as a reflex action. In this action, specific receptors detect specific stimuli. For example, pain in the barefoot due to steeping on a sharp rock was the stimuli. This stimulus was detected by the sensory neurons. The sensory neurons turned this information into a chemical signal which was transported by the interneurons to the motor neurons of the CNS. The CNS detected the signal and gave information for a response as a result of which Santi pulled back his feet.
The possible cause for a decrease in ecosystem productivity is : B. a decrease of the biodiversity o an ecosystem
Decrease in biodiversity means that there will be less organisms that support each other to maintain the balance in the ecosystem, which eventually decrease its productivity
