Answer:
A. two haploid gametes fuse to form a diploid cell
Explanation:
Meiosis is a type of cell division. When a parent cell with "2n" chromosomes enters the process of meiosis, four daughter cells each with "n" chromosomes are formed. This occurs since homologous chromosomes separate from each other during anaphase-I. However, meiosis does not include the fusion of two haploid cells. The fusion of two haploid cells mainly occurs during the process of fertilization during which a haploid male gamete and a haploid female gamete fuse to form a diploid zygote.
Answer:
Respiration
Explanation:
Food energy is chemical energy that animals (including humans) derive from food through the process of cellular respiration. Cellular respiration may either involve the chemical reaction of food molecules with molecular oxygen (aerobic respiration) or the process of reorganizing the food molecules without additional oxygen (anaerobic respiration).
Answer:
Marine mining is a process that can be done by dredging the seabed and is used for the extraction of mineral resources from the seabed, which are non-renewable, with a negative impact on marine ecosystems.
Explanation:
The illustration shows a process of marine mining by dredging, where the resource extracted is of a mineral nature, like copper, zinc, silver and gold. Gravel used for construction can also be extracted from the sea. Mineral resources extracted from the sea are not renewable.
The process of marine mining can be harmful to the ecosystems there, so it must be a process that requires control and management from the ecological point of view.
Two possible consequences of not regulating marine mining are:
- <u><em>Destruction of the habitat of life forms present on the sea floor</em></u><em>, which endangers many species and even forces migration to more stable areas, with consequences on the food chains.
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- <em><u>Extinction of marine species that inhabit the seabed</u></em><em>. The flora and fauna of the sea floor usually have slow reproductive cycles and, in the case of fish, spawning takes place on the bottom of the sea. Mining endangers the reproductive cycles of the species, leading to induced extinction.</em>
Responsible and controlled mining activity can be useful for humans, while avoiding negative consequences on the ecosystems that exist at the seabed.
The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
