<span>Answer: Cellular differentiation is responsible for one daughter cell becoming a sieve tube whereas the other becomes a companion cell. Cell differentiation occurs as different genes are switched on and off.
Hope this answer helps!</span>
Answer:
B, C, Dand E are all correct
Explanation:
Why B is correct- The cell membrane, also known as the plasma membrane, is a double layer of lipids and proteins that surrounds a cell and separates the cytoplasm (the contents of the cell) from its surrounding environment. It is selectively permeable, which means that it only lets certain molecules enter and exit.
Plants, animals, and bacteria have a cell membrane. Why d is correcect
Why C is correct- The cell membrane is not a solid structure. It is made of millions of smaller molecules that create a flexible and porous container. Proteins and phospholipids make up most of the membrane structure.
Why E is correct- The plasma membrane is primarily composed of phospholipids arranged in a bilayer, with the hydrophobic tails on the interior of the membrane, and the hydrophilic heads pointing outwards
Why A Is Not correct- It is very fragile and its role is to hold the cell together and to help control what substances can get in and out. It is partially permeable, allowing only some substances to pass through it. The membrane has a complex structure consisting of a phospholipid bi-layer and different types of proteins.
Photosynthesis is a process by which plants use sunlight, water, and carbon dioxide to produce carbohydrates, and other biological compounds, which reduces the amount of carbon dioxide in the air. This is the difference between plants and animals. The carbon dioxide is stored in the plants until they decompose or are burned. So, for example, each fall when the trees lose their leaves and the plants die the level of carbon in the atmosphere goes up. The rest of the tree, bark etc., does not continue to absorb carbon. Plants only take in carbon so long as they are growing and not after they have reached their natural height. Planting trees and other plants is one component of the solution to global warming, but the number of plants we have now cannot consume more carbon than they already do, and there is some evidence that warmer temperatures make photosynthesis more difficult.
The answer is RESPIRATION
Answer:
Aluminum
Explanation:
The density of Aluminum is 2.7 g/cm3
We know the volume and mass of the unknown metal, as density is mass/volume: 81g/30cm3 = 2.7 g/cm3 which is the density of Aluminum :)
Covalent bonds are formed when two atoms are able to <em>share</em> electrons.
Iroinic bonds are form when two atoms are <em> </em> electrons from each other to complete the bond. This results in a pair of ions.
<u>Covalent bonds:</u>
- Have a definite shape.
- Have a low melting point.
- At room temperature they are in a liquid or gas.
- They occur between two non-metals.
<u>Ionic bonds:</u>
- Have no definite shape.
- Have a high melting point.
- At room temperature they are solid.
- They occur between a metal and a nonmetal.
