To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
While she is still resting, take her resting heart rate first before you can calculate her target heart rate.
Answer:
Made mostly of collagen, bone is living, growing tissue. Collagen is a protein that provides a soft framework, and calcium phosphate is a mineral that adds strength and hardens the framework. This combination of collagen and calcium makes bone strong and flexible enough to withstand stress.
Answer:
Which of the following mechanisms is used by gram-negative bacteria to cross the blood-brain barrier? D) Inducing TNF
Explanation:
The blood brain barrier is a barrier formed by brain microvascular endothelial cells, astrocytes and pericytes. Pathogens can cross this barrier by using different mechanisms. The Tumor Necrosis Factor (TNF) is the way gram-negative bacteria cross this mentioned blood-brain barrier.
Answer:
it increased so fast because as more and more came to be, their genes evolved to allow them to adapt to their surroundings and prededators which allowed them to live longer, strive in the envirnoment and make even more babies.
Explanation:
