Answer: D
Explanation:
Crossing over refers to homologous chrosmomes exchanging DNA which creates variation of chromsoomes that are inheried by offspring.
The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
In a cladogram the tiny indentations along the bottom line is an evolution or change and every organism after the indentation on the bottom line has it and every organism before the indentation does not
Organism
Population
biological community
ecosystem
biome
biosphere
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Population is a group of organisms of d same species
A biological community is the population of organisms living together and interacting in a given area
Ecosystem is the interaction between living and non living organism in a community
Biomes are biological communities that are formed in response to a shared physical environment
Biosphere is the part of the earth that contains living organism
B or A is the answer
Explanation because i know this question before
