6. Channel proteins span the membrane and make hydrophilic tunnels across it, allowing their target molecules to pass through by diffusion.
7. They move freely around the membrane.
8. Binary fission is the division of a single entity into two or more parts and the regeneration of those parts separate the entities resembling the original.
Explanation:
The quantity of energy decreases down each trophic level as only 10% of the energy at the upper level is transferred to the next level, the remaining 90% is lost as heat during metabolic process. Through the energy pyramid we can explain how energy is lost at each trophic level, the number of consumer at each trophic level that will benefit from the transfer of energy depends on the size and quality of the energy from the autotrophs
Calories in and of themselves aren't a reliable way of describing energy density in food. It doesn't reflect what actually happens in your body (look up bomb-calorimeter for how people figure out calorie content in foods). So based on this, the question is a bit of a non-sequitur. But if you disregard that and go with a regular answer, it really depends on what kind of calories you're ingesting because foods get digested in a function of different amounts of time. Carbohydrates will get digested and converted into glucose almost immediately - being very close to 100% energy efficiency. Fats are the slowest as your body needs to produce bile in order to digest it - not enough bile = undigested fat = unused calories. Proteins are turned into either amino acids (not an energy source per se) or converted into glucose like carbs but instead through gluconeogenesis which is a less efficient form of glucose conversion than carbohydrates (since your liver/kidneys need to produce the enzymes to convert it). The efficiency of protein is likely in the range of 50-60% calories. This is just the tip of the iceberg though - your metabolism also plays a part as to how much and when these calories are either used, stored, and excreted by your body. Ever got the meat sweats? That's your body burning excess energy through thermogenesis when you eat too much protein. So it really depends why you're asking because the answer will differ for each scenario.
The spines of the cactus have several functions, which are the following:
To defend them from possible predators: inside the body of the plants there is a great deal of water; if herbivores could access it, these plants would not survive.
To provide them with shade: it is true that not much, but it is enough so that the loss of water by evaporation is minimal.
Reflect sunlight: many species have white spines.
