Answer: it is difficult because it is necessary to understand some concepts used in a system. For example what is a boundary, and environment which can be positive or negative, etc. A sample could be the course OpenLearn that provides an example of Computing & IT.
Explanation:
Like DNA, RNA contains four nitrogenous bases. Three of them are the same as those found in DNA. The one that is different is called uracil. The five-carbon sugar in RNA is called ribose.
Uracil is a crystalline organic molecule, and a component of the ribonucleic acid (RNA). The RNA molecule is made up of a sequence of nucleotides, which individually contains a five-carbon sugar (ribose), a nitrogenous base, and a phosphate group. Uracil is one of the four nitrogenous bases present in the nucleic acid of RNA. The others are adenine, cytosine, and guanine, and are represented by the letters; A, G, C and U. In DNA (deoxyribonucleic acid), the uracil nucleobase is substituted by thymine.
Answer:
Spotted Eagle Rays have two sets of five gills on each side of their body on the ventral side. In order to breathe, A. narinari must be in continuous swimming motion so that oxygen can be absorbed from the water passing through the gills
Explanation:
<span>The answer should be 67.5gram
If Mary wants to consume 15% of her kcalories from protein, then the target calorie would be: 15% * </span><span>1800 kcal= 270kcal.
Every gram of protein will give about 4 kcal of energy. So, the protein needed in gram would be: 270kcal / (4kcal/gram)= 67.5 gram</span>
Answer:
(B) Energy transfer between trophic levels is almost always less than 20% efficient.
Explanation:
The ultimate source of energy on the Earth is the Sun. The energy coming from the Sun is captured by green plants by the photosynthesis. During photosynthesis sun energy is fixed into chemical energy (carbohydrate). So, in an ecosystem energy flow is unidirectional (from sun to the green plants). The fixed chemical energy from green plants is transferred to the herbivores then to carnivores through food. When one organism eats another organisms, only 10 % of the energy present in the organism is transferred as a food for the next organism and a large amount of energy is lost as heat into the environment. Thus, energy keeps on decreasing when stored energy moves from producers to top consumers. Thus, less than 20% energy transfer limits the trophic levels in most of the ecosystem.
