Answer:
D) largest mass extinction event in Earth's history
Explanation:
The cambrian era started following the pre-cambrian extinction
Answer:
This question lacks options, the options are:
A) FF and ff
B) FF and Ff
C) Ff and Ff
D) Ff and ff
The answer is D (Ff and ff for parent 1 and 2 respectively)
Explanation:
This question depicts a single gene coding for fur colour in mice. The gene controls two traits, black fur and white fur, encoded by alleles F and f respectively.
According to the question, a pair of mice has been bred several times to generate the same data of 22 black fur and 23 white fur mice. Based on this data, it shows that the phenotypic ratio of black to white mice is 1:1.
To get a 1:1 phenotypic ratio of black fur offspring to white fur offspring, the parents mice must have genotypes Ff (heterozygous) and ff (same recessive alleles).
In a cross between parents Ff × ff (see punnet square), offsprings with the following genotypes will be produced: Ff, Ff, ff and ff. Ff is black furred while ff is white furred.
Ff (2) : ff (2) is equivalent to Ff (1) : ff (1).
Hence, a data of 22 black mice and 23 white mice which represents a 1:1 ratio will only be produced by parents mice with genotypes: Ff and ff.
Hi
The answer is : C
Transcription Factors
Answer:
The appearance of free oxygen in the Earth's atmosphere led to the Great Oxidation Event. This was triggered by cyanobacteria producing oxygen which developed into multicellular forms as early as 2.3 billion years ago
Explanation:
To clarify what I said here are some questions to help!
How did oxygen first appear?
Whiffs in the air is how oxygen first appeared billions of years ago.
For the most part, scientists agree that oxygen, though lacking in the atmosphere, was likely brewing in the oceans as a byproduct of cyanobacterial photosynthesis as early as 3 billion years ago
When was oxygen found?
2.33 billion years ago
Since its first appearance 2.33 billion years ago, oxygen accumulated in high enough concentrations to have a weathering effect on rocks just 10 million years later.
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