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4 years ago

Scientists know what the first cells were like based on fossil evidence. a. True b. False

Biology

1 answer:

Alika [10]4 years ago

7 0

Answer:

The correct answer will be-True.

Explanation:

Scientists have tried to understand and explain the emergence of life by collecting the evidence that lived in the past which turned into fossils.

The scientists have predicted that earth was formed around 4.5 billion years ago but the first evidence of life belonged to 3.5 billion years ago. The earliest undisputed evidence was a microscopic organism which used sunlight, water and oxygen to synthesize the food and was known as cyanobacteria. These cyanobacteria formed fossils known as "stromatolites".

Recent studied found fossils of bacteria which were formed around 4.5 billion years ago when the earth was still hot and the climate was unstable.

Thus, it is true that fossils act as evidence to support that what were the first cell looked like.

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In fruit flies, one genotype for red eyes is written XRXR. The R stands for the dominant allele for red eyes. What does the X st

Reil [10]

Answer:

The correct answer is : the female chromosome

Explanation:

According to the question, it is mentioned that R is a dominant allele, responsible for the red eyes.
RR is a genotype for Red eyes.
A fruitfly has a diploid genotype which means each trait is represented by a pair of chromosomes.
In the above question, the dominant red eye colour trait is represented by the pair of chromosomes RR.
Therefore, XX must represent another trait.
By convention, a pair of X chromosomes (XX) represent a female and a combination of X and Y chromosomes (XY) represents a male.
Given XX genotype represent a female fruitfly chromosome.

6 0

3 years ago

What is the probability that the first offspring from the cross listed below will be heterozygous for all loci?

Tanya [424]

Answer and Explanation:

Cross: aa Bb dd Ee x AA bb Dd Ee

We can calculate the probability of getting heterozygous individuals in the progeny by using the product rule. Assuming that these four genes assort independently (events that occur independently from each other), we can infer that the F1 will have the next genotypic proportions for each gene:

1) aa x AA

F1) 4/4=1 Aa

2) Bb x bb

F1) ½ bb

½ Bb

3) dd x Dd

F1) ½ dd

½ Dd

4) Ee x Ee

F1) ¼ EE

2/4 = ½ Ee

¼ ee

So, to know what the probability is that the F1 of being heterozygous for all loci, we must multiply the respective individual probabilities of getting a heterozygous genotype, like this:

1 Aa x ½ Bb x ½ Dd x ½ Ee = 1/8 AaBbDdEe

6 0

3 years ago

Which is NOT a property of

disa [49]

Answer:

B. Electromagnetic waves travel in straight lines.

6 0

3 years ago

¿Qué sistemas del cuerpo son los más susceptibles al coronavirus?

blondinia [14]

Answer:

The lungs are the organs most affected by coronavirus

Los pulmones son los órganos más afectados por coronavirus

Explanation:

7 0

3 years ago

The heartworms that can accumulate within the hearts of dogs and other mammals have a pseudocoelom, an alimentary canal, and an

Lyrx [107]

Answer;

Phylum Nematoda.

The heartworms belongs to the phylum Nematoda.

Explanation;

-Phylum Nematoda are un-segmented organisms with anterior lateral chemosensory organs (amphids) and with a persistent blastocoel or pseudocoelom; dorsal and ventral nerve cords in epidermis and excretory system of renette cells or tubules.

-The alimentary canal is provided with distinct mouth and anus (complete digestive tract).

8 0

3 years ago