Answer:
The mechanisms of transport across the cell membrane are as follow: 1- simple diffusion, 2- facilitated diffusion, 3- primary active transport and 4-secondary active transport
Explanation:
The cell membrane is a selectively permeable structure capable of transporting substances by different mechanisms. Simple diffusion is a type of passive transport (i.e. does not require energy) where non-polar molecules (e.g. O2, CO2) pass across the membrane by a process that does not require energy from the cell. Facilitated diffusion is another type of passive transport where larger polar molecules (e.g., glucose and amino acids) pass across the membrane by using specific transmembrane integral proteins. On the other hand, primary active transport is a type of active transport that uses chemical energy (e.g., ATP) to move substances such as metal ions (Na+, K+, Ca2+) across the cell membrane against their concentration gradient. Finally, secondary active transport is another type of active transport where transporter proteins are used to couple the movement of ions (e.g., H+ protons) down their electrochemical gradient to the transport of another ions/solutes against their concentration/ electrochemical gradient.
Answer:B
Explanation:because mercury has a very thin atmosphere.
Stigma is complex for its blend substances. For example, it can trap pollen and prepare pollen grains for fertilization. hope I helped shawty :)
As you can see in the table presented below, all of the gametophytes have seeds do not form in an enclosed structure and <span>undergo alternation of generations (marked in purple)
The gingkos were widespread in the distant past, but are now presented with only one species with fan-like leaves, the Gingko Biloba. (green)
The gnetophytes have three genera with very different looking species. One of the most iconic ones being the Welwitschia mirabilis often called the wise man's beard. (blue)
The conifers include redwoods, like sequoias and all, have pines as leaves and produce cones. (brown)</span>