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4 years ago

4. Why do you think it took so long for scientists to accept the idea of continental drift?

1 answer:

6 0

Scientists could not easily collect data to prove that the earth was once connected. However, after finding similar animals in different parts of the world, that is when they began to consider the theory.

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Part A - Modification of chromatin structure Which statements about the modification of chromatin structure in eukaryotes are tr

Salsk061 [2.6K]

Answer:

Some forms of chromatin modification can be passed on to future generation of cells

Acetylation of histone tails in chromatin allows access to DNA for transcription

DNA is not transcribed when packaged tightly in a condensed form

methylation of histone tails can promote condensation of the chromatin

Explanation:

chromatin modifications that can be passed on includes epigenetic modifications that are heritable changes made to the chromatin structure that does not involve the DNA sequences. Some epigenetic modifications include DNA methylation and Histone modifications. examples of histone modification include acetylation, methylation, phosphorylation, ubiquintylation etc. All these function either in allowing the DNA become more accessible to transcritional factors or vice versa. for exmple, histone tail acetylation encourages unwounding of nucleosomes allowing transcriptional factors to have access to the DNa while histone tails methylation further tightens the nucleosomes promoting condensation of the chromatin.

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4 years ago

The smallest unit of life is a ,and all organisms have at least one.

iogann1982 [59]

Answer: A cell

Explanation:

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3 years ago

Read 2 more answers

You wish to create a mutation in which you prevent access of rna polymerase to the gene. Which region of a gene would you target

Alexus [3.1K]

Answer:

The promoter region/sequence

Explanation:

Promoter sequences/region is where the transcription factors and RNA polymerase must attach before the gene can be transcribed. SO if we mutate this sequence, the transcription factors and RNA polymerase won't recognize it thus would not attach and transcribe the targeted gene.

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3 years ago

Few seeds can be dispersed by more than one method of seed dispersal.’ Explain with suitable examples.

MrMuchimi

Answer:

There are five main modes of seed dispersal: gravity, wind, ballistic, water, and by animals. Some plants are serotinous and only disperse their seeds in response to an environmental stimulus.

Gravity: A good example of gravity dispersal is the marigold flower. When they are ready, these seeds drop to the ground.

Wind: There are two types of wind dispersal adaptations, the floaters, and the fliers:

(wind) Floaters: The common dandelion is a good example of this type of seed dispersal.

(wind) Fliers: Maple seeds grow in pairs, but when they are mature, they separate, and a strong wind can pull them from the stem

Ballistic: Some common examples of this type of dispersal are garden peas. When the cells grow older, the result is that the pods break open and twist. This twisting actions pops the seeds lose and pushes them away from the pod.

Water: Coconuts have a husk that surrounds the seed. This husk is very buoyant and a coconut seed can float across hundreds of miles of ocean before washing ashore on a new island to germinate and grow into a tree.

Animals: there are also two types of these, hitchhikers and edibles. Seeds that stick to the outside of animals, or are spread when they go out the other end after being eaten:

Hitchhikers: Some examples are cockleburs and foxtail.

Edibles: These seeds are surrounded by good tasting fruit, like apples and peaches.

7 0

3 years ago

PLEASE HELP ME PLEASE

VMariaS [17]

Most of the mutations have no effects whatsoever on the organisms but some can be dangerous. There are two types of mutations that cause harm to the organism's ability to survive:teratogen muations are the mutations that form inside the uterus when the fetus is still developing and can even kill it or cause severe malformations that lead to death in the early life. Carcinogen mutations are the ones that lead to the formation of neoplasms(masses of cells that divide uncontrollably, basicly cancer).

8 0

3 years ago