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kow [346]
4 years ago
8

When did Cyanobacteria start producing pure oxygen

Biology
2 answers:
AleksandrR [38]4 years ago
8 0

Answer:

After the hadeon

Explanation:

Travka [436]4 years ago
3 0

<u>Answer:</u>

Cyanobacteria start producing pure oxygen around 200 million years ago.

<u>Explanation:</u>

Many scientists believed that Earth did not have any oxygen. Cyanobacteria or the blue green algae are the microbes which produced oxygen for the first time with the help of photosynthesis.  This was around 4.5 billion years ago: after Hadean eon.

They were very simple, but they produced oxygen in the early earth’s atmosphere. So, they brought evolution on earth. This “blue-green algae” exists in salt water, rocks and soils and play a major role in maintaining the ecosystem.

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The blood cells containing hemoglobin, an iron-containing protein that transports oxygen, are called __________.
Otrada [13]
<span><span>The blood cells containing hemoglobin,  that transports oxygen (O2) to the body tissues of vertebrates, are called red blood cells.</span> Red blood cells (RBCs), are also referred to as red cells, red blood corpuscles, haematids, erythroid cells or erythrocytes<span>, (from Greek erythros for "red" and kytos for "hollow vessel"..RBCs take up oxygen in the lungs and release it into tissues while squeezing through the body's capillaries.</span></span>

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7 0
3 years ago
Who was the first person to see cells?
Stella [2.4K]
<span>Robert Hooke was the first person to see cells.</span>
6 0
3 years ago
An estuary is ___
emmainna [20.7K]

Answer:

<em>The correct option is d)  an ecotone</em>

Explanation:

An ecotone can be described as an area of transition between two different biomes. An estuary can be described as an ecotone where the river water meets the seawater. The freshwater biome mixes with the seawater biome in an estuary. Unique plants and animals are grown in an estuary which are adapted to live in such an environment. The water present in an estuary is termed as brackish water. Hence, the correct option is d.

5 0
3 years ago
Read 2 more answers
A forest habitat contains a great deal of plant and animal life. Using the forest habitat as a model, explain the difference bet
Vanyuwa [196]
OK, richness you do have to depend on any one

4 0
3 years ago
If a homozygous black bull is mated with a homozygous white cow and the calf is gray, this could be an example of ___________. H
givi [52]

Answer:

Incomplete dominance

Co-dominance

Explanation:

Gregor Mendel discovered the principles that governs heredity, in which one of them is that an allele called DOMINANT allele, is capable of masking the expression of its variant allele called RECESSIVE allele in a heterozygous state. However, there has been genetic scenarios contrary to this his LAW OF DOMINANCE.

One of those Non-mendelian pattern of inheritance is a phenomenon called INCOMPLETE DOMINANCE, where an allele does not mask the expression of another completely, instead their combined state produces a third intermediate phenotype that is different from both parents. This is the case of the homozygous black bull mated with a homozygous white cow to produce a grey calf. The grey phenotype is an intermediate phenotype of both the black and white colours that forms due to incomplete dominance.

Another genetic scenario is called CO-DOMINANCE, where one allele is neither dominant nor recessive to the other allele, but instead both phenotypes becomes simultaneously expressed in the heterozygous offspring. In this case, the black bull and white cow were mated to form a heterozygous calf with both black and white spots.

3 0
3 years ago
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