Answer:
Prophase 1
Explanation:
Prophase I :It can be divided into five stages:
1)Leplotene: In this stage, chromosome becomes visible and shorten as a single structure.
2)Zygotene: Homologous / sister chromosome pair up. This process is known as synapse. Synapse is the process of attachment of homologous /sister chromosome. One pair comes from the male parent while the other comes from the female parent.
3)Pachytene: Bivalents shorten.
4)Diplotene:Point of attachment of non-sister chromatids. The two chromosomes are seen to be joined at several points along their length. These points are known as Chiasmata.(Chiasmata, a cross). The paternal gene A, B, C may swap for the maternal gene a, b, c for instance, leading to a new gene combination in the resulting chromatids. This is referred to as *CROSSING OVER*.
5)Diakenesis: Homologous centromere move apart.
So, crossing over occurs in *Prophase 1.
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Answer:
Explanation:
Cell which is the basic unit of life is affected by the interactions with biotic and abiotic factors such as temperature, sunlight. Organisms are made up of cells and they respond differently to temperature changes, sunlight, water availability. Some cell perform better at some certain range of temperature while some cannot.
Organism itself are affected by the interaction of some of this factors this include water and nutrients availability. Distribution of organism in a particular habitat is greatly influenced by availability of water and nutrients it lead to competition for survival among organism. Population density and species diversity also influence community and ecosystem. Population determines how resources is allocated in a community and it affect the activities of the organism in that domain or territory.
Answer:
B. Maintenance of homeostasis by negative feedback
Explanation:
A negative feedback loop is one where the body responds by changing the expected outcome.
So as the runner's body temperature increases, they perspire, which LOWERS their body temperature. This means that perspiring is a response that changes the original response, as their body temperature decreases rather than continuing to increase from exertion.
