Answer:
There are three main types of blood vessels:
1)Artery ---
i) It is a blood vessel having a thick wall.
ii) It carries blood from the heart to different parts of the body.
iii) On regulatory demand of the body it can dilate or constrict.
iv) It doesn't contain any valve.
v) All arteries carry oxygenated blood except the pulmonary artery.
2)Vein ---
i) It is a blood vessel having a thin wall.
ii) It brings blood from different parts to the heart.
iii) It can't dilate or constrict under normal conditions.
iv) It contains valves that allow the blood to flow in one direction towards the heart.
v) All veins carry deoxygenated blood except the pulmonary vein.
3)Capillary ---
i) It is a very narrow blood vessel that has very thin walls.
ii) It forms a network throughout the body in all living cells connecting arteries to veins.
iii) It can dilate or constrict according to the requirement of tissue.
iv) It doesn't have any valve.
v) It contains mixed blood as it connects arteries and veins
Yes, it's A. Spinach and cabbage are (A) the leaves of plants. Spinach do have flowers but they are not the flowers itself while cabbages don't have flowers. Cabbages and Spinach don't have fruits either.
The correct answer for question number 1 is A - eukaryotes are the name
for unicellular organisms that dominated earth up to the Precambrian
times.
The correct answer for question number 2 is C - the
greenhouse effect is related to the phenomenon of an increase in average
surface temperature known as global warming.
The correct
answer for question number 3 is D - the colourless and odourless gas
that is produced by the radioactive decay of Uranium-238 and is considered
to be a cancer-causing agent is Radon.
The correct answer for
question number 4 is B - Scientists can determine if oxygen existed in
Earth's Archean atmosphere by looking for oxidized iron in rocks.
Answer:
- Diploid → Prophase, metaphase, and anaphase
- Haploid → Telophase
Explanation:
During prophase I, chromosomes get condensed. Each of the chromosomes gets in pair with its homologous one. They do so to make the crossing-over possible, a stage where they interchange their parts → 2n
During metaphase I, each of the homologous pairs is driven to the equatorial plane, where they randomly line up → 2n
During anaphase I, occurs the independent separation of homologous chromosomes that migrate to opposite poles of the cell. This separation generates different chromosomal combinations in the daughter cells. There are two alternatives per homologous pair → 2n
In telophase I, half of the chromosomes are already in one of the poles, while the other half is on the other pole. Each group of chromosomes has now half the number of the original cell. The nuclear membrane forms again in each pole → n
Finally, occurs cytokinesis, which involves the invagination of the cell membrane and cytoplasmic division.
The two new cells are ready for meiosis II.
