<u>D.) Crossing over</u> is a source of genetic variation that involves the swapping of sections of chromosomes during meiosis.
Answer:
so the most h2o which is A
Explanation:
1) Ecology is the scientific study of the distribution and abundance of organisms, the interaction among organisms, and the interactions between organisms and their abiotic environment. Ecologists try to understand the inner workings of natural ecosystems and the species they contain.
2) Ecosystems have no particular size. An ecosystem can be as large as a desert or a lake or as small as a tree or a puddle. If you have a terrarium, that is an artificial ecosystem. The water, water temperature, plants, animals, air, light and soil all work together.
3) The biotic factors of an ecosystem include all the populations in a habitat, such as all the species of plants, animals, and fungi, as well as all the micro-organisms. Also recall that the nonliving factors are called abiotic factors. Abiotic factors include temperature, water, soil, and air.
4) For aquatic ecosystems, these factors include light levels, water flow rate, temperature, dissolved oxygen, acidity (pH), salinity and depth.
Hope this helped. ;)
The products of the digestive system are actually tied directly to the circulatory system in that the organs of the digestive system are used to turn ingested food into products that can be absorbed by the blood and then carried to other organs for use as energy or other functions.There are also several links between the digestive system and the respiratory system in that there are organs and muscles that serve both, for example the diaphragm which works to force air into and out of the lungs as well as to force waste products out of the digestive system.<span>All of the systems have to work together as well, without the intake of oxygen and exhalation of carbon dioxide, the function of the digestive system would grind to a halt. Without the production of glycogen and other things necessary for muscular function, produced by the digestive system and then distributed by the circulatory system, all three functions would cease.</span>
