<span>Osteoclasts
</span><span>Are derived from stem cells that produce macrophages
Secrete acids and protein-digesting enzymes</span>
Answer:
skeletal muscles control his leg movement and cardiac muscles control his heart rate
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).
Black death, also known as the bubonic plague was one of the worst pandemics that ever happened, killing around 1/3 of Europe's population. It spread to Europe in the mid 1300's from China.
Black death victims were treated through magic, witchcraft, prayer and other methods. As for the two other options, they used medicine, but not antibiotics and radiation hadn't been discovered yet (it was discovered in the 1900's)
