Answer:
Common to all plant species, the cell wall is the tough outer coat that protects the plant cell. The cell wall is mostly carbohydrate‐based, comprising three major classes of polysaccharides: cellulose, hemicellulose and pectin. There are also important structural proteins as well as phenolic and aliphatic polymers.
Explanation:
Answer:
c
Explanation:
tumors are made from uncontroled tussue cell division
Answer:
The source of Calcium (Ca⁺⁺) for the skeletal muscle cells is the sarcoplasmic reticulum, the main store of intracellular Ca⁺⁺.
Explanation:
Calcium (Ca⁺⁺) is an ion that plays an important role in muscle contraction, a process that requires high cytoplasmic concentrations of this ion to promote myofibrillary activity.
The sarcoplasmic reticulum (SR) -equivalent to the endoplasmic smooth reticulum- is an organelle that regulates the contractile activity of skeletal muscle. The two terminal cisterns of the SR attach to the T-tube, forming a triad, which surrounds the myofibrilla.
Once the muscle cell receives the signal to contract, the Ca⁺⁺ channels are opened and allow Ca⁺⁺ to enter the cell, promoting the exit of this cation from the SR and increased its cytoplasmic levels. This stimulates muscle contraction.
Answer:
B. small heart-like pumps
Explanation:
Small heart-like pumps is a mechanism that is NOT used to propel lymphs through lymphatic vessels.
Answer:
A) It uses less energy to make something from recycled materials than from new materials.
Explanation:
When a recycled material is used to make a new product, it conserves energy because the recycled materials have already been processed once; so making something from it for the second time uses less energy-intensive than the first. For example: Making new aluminium from old products uses 95% less energy than making it from scratch.
Hence, the correct answer is "A)"
