Answer:
Insects use air-filled tubes called tracheae to exchange oxygen and carbon dioxide between their tissues and the air. This network of tubes is also called a tracheal system. Insect body contains small openings on the outer surface called spiracles. Spiracles are connected to the internal tubes.
Pandas live for about 20 or so years
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.
