<span>Damming a river has a variety of effects on the freshwater ecosystem, more than just altering the flow from A to B. Dams create calm bodies of water, changing overall temperature regimes and sediment transport, leading to conditions which tend to favour generalist species. Loss of specialist species, particularly endemics, changes the community structure and leads to biotic homogenization. A dam will withhold sediment in the reservoir, not just decreasing the amount of substrate available to local freshwater species, but even impacting diadromous, estuarine and marine species much further downstream. The competition between resident species for food and breeding sites will increase as damming isolates populations, and perhaps more importantly, damming completely restricts migratory fish species. Isolation may lead to decreases in genetic diversity and therefore puts species at greater risk from disease. All of these effects may be exacerbated by changes in the surrounding land use. Overall, damming river flow will lead to both a loss of native species, but also an increase in exotic species which are more likely to become established in degraded habitats. For this reason, dams are one of the greatest global threats to freshwater biodiversity.</span>
Answer:
the answer is c I promise
Explanation:
I just took the test
Answer:
The correct answer will be option-pollen.
Explanation:
The pollen are the male gametophyte which is produced in the seed plants.
The pollen produce male gametes after entering the female gametophyte. The male gametes fuse with the egg cell and form the embryo inside ovary which matures and forms seeds. The vascular seed plants lack these pollen but instead produces male gametes in gametangia which are replaced by the pollen in the seed plants.
Thus, option-pollen is the correct answer.
oo, The Big Bang theory predicts how much of each element should have been made in the early universe, and what we see in very distant galaxies and old stars is just right. You cannot look in new stars, like the Sun, for this evidence, because they contain elements that were created in previous generations of stars.
i hope you will get some knowledge from here❣
Answer
I added 4 and 5 as an attachment due to time constraint.
Explanation:
1. at a steady state ca2+ taken by vesicle = 40n/mol
enclosed volume of CSR = 5μ/mg
concentration of ca2+ in vesicle =
40*10⁻⁶/5x10⁻⁶
= 0.008
= 8x10⁻⁹mol/L
2. radius of circle =75nM
volume = 150nm
volume of vesicle = 4/3 x pi x r³
= 1.33 x 3.14 x (75x10⁻⁹)³
= 1.77 x 10⁻²¹
when we convert this we get
1.77x10⁻¹⁸L since 1m³ is equal to 100oL
surface area =4x3.14x(75x10⁻⁹)²
= 12.56x5.625⁻¹⁵
= 7.065x10⁻¹⁴m²
this is 7.065x10⁻¹⁰cm²
3. number of vesicle/CSR
= 5x10⁻⁶/1.77x10⁻¹⁸
= 2.824x10¹²
surface are = 2.824x10¹² x7.06x10⁻¹⁰
= 19.95x10²
