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olga55 [171]
4 years ago
8

What created oxygen in the early atmosphere

Biology
1 answer:
Molodets [167]4 years ago
6 0
Oxygen was created by the first signs of photosynthesis, done by plants and algae. =)
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Why is it dangerous or bad for babies to be born too small or too early?
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It’s dangerous for babies to be born early because not all of the baby’s organs and bones may have not developed fully yet. Premature babies could also develop a bunch of different health problems such as asthma or feeding problems.
3 0
3 years ago
Write a sentence using an example of active transport. I also need to do the same thing with passive transport.
Harrizon [31]
Active transport uses energy such as plants taking in minerals while passive transport is opposite as it does not use energy.
8 0
4 years ago
What occurs during nondisjunction and the effect of the resulting cells
Llana [10]

Answer:

Failure of chromosome to separate

Explanation:

The main essence of meiotic division is to form daughter cells with a reduced number of chromosomes that will maintain the correct chromosomal number in an organism. This is achieved when chromosomes separate during gamete formation (meiosis) to produce haploid (n) gametes.

However, a case may arise whereby chromosomes fail to separate during the anaphase stage of meiosis. This case is referred to as MEIOTIC NON-DISJUNCTION. As meiosis occurs in two stages i.e. meiosis I and II, so does meiotic nondisjunction. It can occur in meiosis I, where homologous chromosomes fail to separate or meiosis II, where sister chromatids fail to separate.

If it occurs in meiosis I, Two gametes will have a n-1 chromosome number i.e. one chromosome is missing while Two other gametes will have n+1 chromosome number i.e. one extra chromosome is added.

If it occurs in meiosis II, two normal haploid gametes (n) will be produced while the other two will have a n+1 and n-1 chromosome number respectively.

When these abnormal gametes (n+1, n-1) fuses with a normal gamete (n), the resulting organisms possess a chromosomal anomaly called ANEUPLOIDY i.e. a disorder in chromosomal number. The organisms will have 47 and 45 chromosomes depending on whether n+1 or n-1 gametes is involved respectively.

4 0
4 years ago
It is recommended that children eat foods high in calcium and iron as a way to reduce the accumulation of lead in their cells an
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sashaice [31]
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4 years ago
Read 2 more answers
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