Answer: True
Explanation:
<u>A cell membrane consists of a lipid bilayer made of polar phosphate head and a nonpolar lipid tail.</u> It is semipermeable and regulates the transport of materials through it. For this,<u> it is selectively permeable</u> and since it is made of lipids, hydrophobic and small polar molecules can diffuse easily through it by simple diffusion and down their concentration gradient. However, polar molecules, large molecules (such as glucose) and ions are not able to pass through it because they are repelled.
To accomplish the transport of these molecules that can not diffuse, proteins embebbed in the membrane function as carriers that enable the transport of polar molecules, large molecules and ions by passive (through facilitated diffusion, down its concentration gradient) or active transport (movement against its concentration gradient).
Parenchyma is the answer because whereas the other two, xylem and phloem are vascular tissues, parenchyma is a packing tissue.
Answer:
The alveolar walls and capillary walls share a membrane. That's how close they're getting. This allows oxygen and carbon dioxide to readily pass from the respiratory system to the circulation. Oxygen molecules bind to red blood cells as they return to the heart.
The purpose of the Open Door Policy was to collaborate with other nations to maintain a common price level for free trade in China. The Open Door policy started in 1899. The correct answer is B.
Answer:
Explanation:
Exons can be shuffled independently known as exon shuffling. It can be done in various ways, leading to infinite number of combinations to discover new and meaningful coding sequences hence various proteins. Due to exon shuffling, evolution need not occur only by the slow accumulation of point mutations but might also move ahead by “quantum leaps” with new proteins appearing in a single generation.