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3 years ago

Difference between embryoblast and trophoblast

Biology

1 answer:

yan [13]3 years ago

4 0

Answer:

The region where the embryoblast contacts the trophoblast is called the embryonic pole. ... Just before implantation, the cells in the embryoblast start to differentiate into two layers - the epiblast (primary ectoderm), and an internal layer of cuboidal cells called the hypoblast (or primary endoderm).

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A dogfish shark contains 24 chromosomes in each of its muscle cells. How many chromosomes are normally found in each of its game

mojhsa [17]

The answer is 2) 12 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

3 0

3 years ago

The organisms that exist now on earth, are the same as thousands of years ago?

cestrela7 [59]

Answer:

A sea sponge 760 million years old

Explanation:

It's unclear exactly how long sea sponges have been around, but they are at least old enough to be the longest-existing creatures on Earth, outside the realm of microorganisms (like bactery). The oldest evidence of a sea sponge found was a fossil discovered just last year in a 760-million-year-old rock. This beat the previous record for oldest sponge fossil, a 635-milloon-year-old sponge discovered in 2009. There may be still older fossils yet to find. But finding an older species is unlikely,as these simple organisms appear to be the progenitors of much more complicated life, including the first multicellular animals.

5 0

4 years ago

The first P-wave of an earthquake took 11 minutes to travel to a seismic station from the epicenter of the earthquake. What is t

iris [78.8K]

Answer:

$\large \boxed{\text{5280 km; 25.5 min }}$

Explanation:

1. Distance from epicentre

The average speed of P-waves is about 8 km/s.

(a) Convert minutes to seconds

$\text{Time} = \text{11 min} \times \dfrac{\text{60 s}}{\text{1 min}} = \text{660 s}$

(b) Calculate the distance

$\text{Distance} = \text{ speed} \times \text{time} = \dfrac{\text{8 km}}{\text{1 s}} \times \text{660 s} = \textbf{5280 km}\\\\\text{The seismic station's distance to the epicentre is $\large \boxed{\textbf{5280 km}}$}$

2. Time for S-wave

The average speed for an S-wave is about 3.45 km/s.

$\begin{array}{rcl}\text{Distance} & = & \text{speed} \times \text{time}\\\text{5280 km} & = & \dfrac{\text{3.45 km}}{\text{1 s}} \times \text{time}\\\\5280 \times \text{1 s} & = & 3.45 \times \text{time}\\\text{Time} & = & \dfrac{\text{5280 s}}{3.45}\\\\ & = & \text{1530 s}\\& = & \textbf{25.5 min}\\\end{array}\\\text{It took the first S-wave $\large \boxed{\textbf{25.5 min}}$ to arrive.}$

8 0

3 years ago

Platelets release a vasoconstricting substance called:.

german

Answer: Platelets release a vasoconstricting substance called <u>SEROTONIN.</u>

8 0

3 years ago

Explain how solar energy is transformed during photosynthesis

Pie

Answer:

Solar energy is used and made into chemical energy that is glucose used water and carbon dioxide (CO2) and also Oxygen (O2) is released as a output as well

Hope This Helped

7 0

2 years ago