Answer:
sexual selection
natural selection
Explanation:
Natural selection is an evolutionary mechanism (changes the allele frequency) by favouring traits that are advantageous among others because they increase the survival and reproduction. In the example above, mosquitofish that live in the predator-rich ponds devoloped a trait that help them survive (swimming in short, fast bursts). This adaptation to environment is favourable by natural selection.
Sexual selection refers to the female mosquitofish and the fact that they choose their males (with better reproductive success).
<span>b The growth of teeth in chickens supports the hypothesis of a common ancestor between birds and reptiles. This is a generally accepted hypothesis, and i'd go with this answer. Obviously we can't say whether chickens will have teeth with certainty, the chickens with teeth are clearly still chickens, and a baby croc isn't hatching out of a chicken egg any time soon.
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Physical exercise preserves bone mass. Measurements of bone biomarkers may reflect the events in bone during exercise. Fifteen healthy, well-trained individuals (7 men and 8 women) performed a running test for 21 min until exhaustion. Venous blood samples were drawn before and 30 min after the exercise to measure the levels of osteocalcin, the carboxyterminal propeptide of type I procollagen (PICP) and the carboxyterminal cross-linked telopeptide of type I collagen (ICTP). After exercise, the women had a marked increase in serum osteocalcin concentrations (from 7.5±5.0 μg/1 to 11.5±3.0 μg/1), whereas the level was unaffected in the men (from 14.5±3.0 μg/1 to 13.5±4.6 μg/l). In the men there was a marked increase in PICP (from 240±47 μg/1 to 268±56 μg/1) that was not seen in the women (from 244±70 μg/1 to 253±60 μg/1). In neither group did ICTP levels change. In conclusion, significant responses were seen in PICP and osteocalcin during exercise, indicating that such measurements may be valuable for the further delineation of the effects of physical activity on bone. Furthermore, the different responses in men and women point to interesting areas for future studies.
Answer:
Don't worry I'm here to help
Explanation:
The ocean plays an important part in the carbon cycle.
- Overall, the ocean is called a carbon 'sink' because it takes up more carbon from the atmosphere than it gives up.
- Photosynthesis by tiny marine plants (phytoplankton) in the sunlit surface waters turns the carbon into organic matter.
Glad I could help!!
Function of an enzyme is to lower reaction's activation energy and to increase speed of a reaction, but to make it happen, enzyme and substrate must fit spatially. The shape of an enzyme is essential to make enzyme-substrate complex - if active site of an enzyme doesn't fit to substrate, there won't be a enzyme-catalised reaction.
