By studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth. There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they have left few traces behind. This is why scientists cannot be certain about how life began.
Answer:
1. 1/2
2. 1/2
3. 1/4
Explanation:
Let the allele for freckles be A or a while that of dimples be B or b.
A person without freckles but heterozygous for dimples = aaBb
A person who has freckles (whose mother has no freckles) but no dimples = Aabb
aaBb x Aabb
Offspring
4 AaBb - freckled and dimpled
4 Aabb - freckled and non dimpled
4 aaBb - non freckled and dimpled
4 aabb - non freckled and non dimpled
1. <em>Probability that the parents will have a dimpled child</em> = 8/16 or 1/2
2. <em>Probability that they will have a child with freckles</em> = 8/16 or 1/2
3. <em>Probability that they will have a child with freckles and dimples</em> = 4/16 or 1/4
<u>See the attached image for the Punnet's square analysis of the cross</u>
I believe the correct answer is "Carbon dioxide"
Answer:
The prolonged electrical depolarization of cardiac muscle cells -that occurs during contraction- is due primarily to the persistent influx of calcium ion
Explanation:
The action potential of the heart muscle is longer with respect to skeletal muscle (around 300 milliseconds), and this is due to the activity of calcium (Ca⁺⁺ ) in the intracellular compartment.
The initial depolarization of cardiac muscle fiber depends on the entry of sodium (Na⁺) into the cell. However, for the action potential to occur and be maintained, Ca⁺⁺ must increase its cytoplasmic levels, which depends on:
- The increase in intracellular sodium induces the release of Ca⁺⁺ from the sarcoplasmic reticulum.
- Calcium entry from the extracellular space through the voltage dependent Ca⁺⁺ channels.
- The entry of extracellular Ca⁺⁺ causes the release of more Ca⁺⁺ ions by the sarcoplasmic reticulum, further increasing its intracellular concentration.
This is how the ion that guarantees the duration of the action potential of the cardiac muscle cell is the Ca⁺⁺.
Learn more:
Calcium, sodium and cardiac muscle cells brainly.com/question/4473795
Answer:
Topographic Map Symbols
Topographic maps use symbols to represent natural and human constructed features found in the environment. The symbols used to represent features can be of three types: points, lines, and polygons. Points are used to depict features like bridges and buildings.
Explanation:
