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AveGali [126]
3 years ago
6

David is a research scientist who is giving a lecture to a class of students on how life began on Earth. Help him complete the s

entences.
Scientists have found
containing fossilized cyanobacteria (blue-green algae). They show that life has been present on the Earth from early ages. Oparin and Haldane were two scientists who hypothesized that life needed reducing environments initially to appear. The ocean in the early ages was
(devoid of oxygen) and acidic.
Biology
2 answers:
Vlad [161]3 years ago
6 0

Answer:

"Scientists have found containing fossilized cyanobacteria (blue-green algae). They show that life has been present on the Earth from early ages. Oparin and Haldane were two scientists who hypothesized that life needed reducing environments initially to appear. The ocean in the early ages was (devoid of oxygen) and acidic."

However, the cyanobacteria produced oxygen as a waste product, as cyanobacteria are photosynthetic. This eventually lead to the Great Oxygenation Event, as this nearly killed off the cyanobacteria as a whole. Although, a few plants at this time used oxygen in their own metabolic processes. This allowed these plants to grow and breed faster. This lead to today, where the majority of multi-cellular life on Earth started from these oxygen-sucking plants, not the cyanobacteria.

Explanation:

sammy [17]3 years ago
5 0

Answer:It was both toxic and regulare

Explanation:

Toxicity depended on the area.

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Mrs. Gibbs cannot seem to catch up with the eating habits of her 14-year-old daughter Zondra and 16-year-old son Austin. Her wee
Alex787 [66]

Answer: The answer is 2200 calories per day for Zondra and 3000 per day for Austin

Explanation:

The options are;

a. 1800 calories per day for Zondra and 2200 per day for Austin

 b. 2200 calories per day for Zondra and 3000 per day for Austin

 c. 2400 calories per day for each of them

 d. 2000 calories per day for each of them

The answer is option B -2200 calories per day for Zondra and 3000 per day for Austin

Calories provide energy which we use to perform daily activities. The calories derived from food allow us take part in important activities and leisure. Calorie needs are often higher during teenage years because it is the time of rapid growth.

Austin, is her 16 year old son. The recommended calorie needs for adolescent males between the ages of 16- 18 are; 2,400 calories for non active adolescents, 2,800 calories for moderately active adolescents and 3200 calories for active adolescents.

Zondra is a 14 year old female adolescents. The recommended needs for adolescent females between the ages of 14-18 are; 1,800 calories for non active adolescent females, 2,000 calories for moderately active and 2,400 calories for active adolescent females.

Option B, 2200 calories per day for Zondra and 3000 per day for Austin  fall within the range

3 0
3 years ago
The major difference between earth and other planets in our solar system is that
babymother [125]

Answer:

Is that earth is the only planet with water and an atomoushpere that allows us to breath in

Explanation:

6 0
3 years ago
in addition to keratinocytes, the stratum spinosum also contains another epidermal cell type called epidermal ______ cells that
WARRIOR [948]

Keratinocytes are differentiated skin cells found in the outermost layer of the epidermis. Dendritic cells are antigen-presenting cells that play important roles in the adaptive immune response.

  • In addition to keratinocytes, the <em>stratum spinosum</em> also contains another epidermal cell type called epidermal DENDRITIC cells that help to fight infection.

  • The s<em>tratum spinosum</em><em> </em>is an epidermal skin layer between the <em>stratum granulosum </em>and<em> stratum basale</em>.

  • Dendritic cells are antigen-presenting cells that are capable of processing harmful antigens in order to present them on the cell surface to the T cells of the immune system.

Learn more in:

brainly.com/question/6955146?referrer=searchResults

5 0
2 years ago
Why would a mutation that involves a centromere have a greater impact than a mutation that occurs elsewhere on a chromosome?
RideAnS [48]
If mutation is associated with the centromere region, the direct impact would be on the segregating mechanism during cell division process.
4 0
3 years ago
4. Which of the following elements does not want to have eight valence electrons? a. magnesium c. hydrogen b. oxygen d. nitrogen
Cloud [144]

Answer:

Hydrogen.

Explanation:

Hydrogen is the simplest chemical element that exists. The symbol for the chemical element Hydrogen is "H" and it is a colourless, tasteless, odorless, and highly flammable gas.

Hydrogen is a chemical element found in group (1) of the periodic table and as such it has one (1) electrons in its outermost shell. Therefore, Hydrogen has an atomic number of one (1) and a single valence electrons because it has only one proton and one electron in its nucleus.

Based on the octet rule which states that atoms of chemical elements gain, lose or share electrons so as to have eight (8) electrons in their valence shell. Therefore, atoms of chemical elements bond in order to attain the electronic configuration of a noble gas i.e a full valence shell which comprises of eight (8) electrons.

However, the chemical element "Hydrogen" is an exception to the octet rule because it is only able to hold a maximum of two (2) valence electrons in its outermost shell to become full.

<em>Hence, Hydrogen is an element which does not want to have eight valence electrons. </em>

7 0
3 years ago
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