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3 years ago

Which of the following statements is true?

Biology

2 answers:

Sonja [21]3 years ago

5 0

C gravity and muscle contractions move food down the esophagus. These muscle contractions are called peristalsis

Nataly_w [17]3 years ago

5 0

D gravity and muscle contractions move down the esophagus

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How exposing enzymes to a UV light for a set time affect its ability to function?

nevsk [136]

The longer the wavelength of light, the deeper the penetration of the light into the skin.

Hope this helps! :P

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3 years ago

Can you identify the steps in the scientific method that correspond to hunt's experiments?

Sphinxa [80]

The team of Hunt had designed an experiment to test the hypothesis of the effect of BPA on mice. The daily doses of BPA was administered into the female groups of mice for 3, 5 and 7 days and then the genetic abnormalities which occured during meiosis, chromosome division or egg formation were studied.

The steps followed in this experiment in order are as follows:

Observation- The mice eggs in plastic cages when washed using harsh soap showed problems during the cell division stage which caused genetic abnormalities.
Question- If the bisphenol A from the plastic affected mice in the damaged cages.
Hypothesis- If the frequency of the genetic abnormality was affected by the exposure to bisphenol A.
Prediction- The level of exposure of mice to bisphenol A was proportional to the increase in genetic abnormalities.

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3 years ago

Which of the following statements best compares genetic diversity in eukaryotes and prokaryotes?

cestrela7 [59]

Answer:

C. Mutations increase the genetic diversity in both prokaryotes and eukaryotes.

Explanation:

It is a well-established fact that mutations increase the genetic diversity in living organisms (especially if they are positive mutations). The positive and faster mutations will help the organism to develop better traits for survival in the changing environments.

The other options are incorrect because of the following reasons:

A. Eukaryotes don't do gene transfer via conjugation.

B. Eukaryotic species don't experience a greater rate of mutations as compared to the prokaryotes. Prokaryotes have a faster mutation rate. This is the reason that microbes can adapt to changing environments faster than humans or other multicellular organisms.

D. As mentioned above, sexually reproducing eukaryotic species evolves slower than the asexually reproducing species. For example, evolution in bacteria (e.g. drug resistance) is faster than any organism belonging to eukaryotic lineage.

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3 years ago

Each body cell of a chimpanzee contains 48 chromosomes. After mitosis, how many chromosomes are present in each cell?

nekit [7.7K]

Answer:

During both mitosis and meiosis, DNA replicates first during S phase of interphase. Each copy (DNA molecule) is called chromatid. Before anaphase they remain together, joined by the centromere in the chromosome.

Part 1: How many chromatids and chromosomes are present at:

(a) anaphase of mitosis: During this phase sister chromatids split. We would have 48 chromosomes in each pole and 48 chromatides.

(b) anaphase I of meiosis: During this phase homologous chromosomes split, being a reductional division. In each pole we will have half the chromosomes we had after DNA replication. This is 24 chromosomes but 48 chromatides (remember they will split during anaphase II).

(c) anaphase II of meiosis: This is an equational division, we will have 24 chromosomes in each pole and 24 chromatides. Each chromatid is considered a chromosome.

(d) G1 prior to mitosis: During this phase DNA has not replicated yet and it is not condensed either. This formed is called chromatin. We will assign one chromatid for each chromosome. This is a somatic cell, so: 48 chromosomes and 48 chromatids.

(e) G2 prior to mitosis: After S phase, we have duplicated all chromosomes. We will assign two chromatids per chromosome: this is 96 chromatides and 48 chromosomes.

(f) G1 prior to meiosis: Before DNA duplication, 48 chromosomes, 48 chromatids.

(g) Prophase of meiosis I: After DNA replication, condensation of the chromatin takes place: 48 chromosomes, 96 chromatids.

Part 2: How many chromatids or chromosomes are present in:

(h) An oogonial cell prior to S phase: This is G1 phase, 48 chromosomes.

(i) A spermatide: This is the male haploid gametid, after meiosis: 24 chromosomes and 24 chromatids.

(j) A primary oocyte arrested prior to ovulation: They are arrested at prophase I of meiosis. This means their DNA is still duplicated and chromatides have not divided yet. 48 chromosomes and 96 chromatids.

(k) A secondary oocyte arrested prior to fertilization: They are halted at metaphase II of meiosis, meaning they have half the chromosomes (24) but chromatids are still together (48).

(l) A second polar body: They suffered the same process as the mature ovum but remained with little cytoplasm. They have 24 chromosomes and 24 chromatids.

(m) A chimpanzee sperm: They have completed both meiosis as well, they have 24 chromosomes and 24 chromatids.

Explanation:

7 0

2 years ago

Read 2 more answers

"which pathogens consist of bits of nucleic acid within a protein coat?"

Novosadov [1.4K]

Hey there,

Answer:

Viruses

Hope this helps :D

<em>~Top♥</em>

8 0

3 years ago