Answer:
The study of DNA started much before the discoveries of Rosalind Franklin and Maurice Wilkins. Nucleus of cell was discovered by Robert Brown in 1831 but the material present inside the nucleus called "nuclein" (DNA) came from the studies of Johann Friedrich Miescher in 1869.
Explanation:
Answer :
Vinegar is a weak acid. This is used to make a naked egg. When an egg is added in the vinegar for one day / 24 hrs, it reacts with the eggshell. The calcium carbonate shell gets dissolve.
Then an egg without shell is formed and the size of the egg does not change. The calcium carbonate reacts with acetic acid and forms carbon dioxide.
When the shell-less egg is kept in the vinegar for 48 hrs i.e. 2 days again, the water content in it enters into the eggs through the membrane. Then the egg gets somewhat bigger.
Otherwise, for 24 hrs, vinegar is acting like an isotonic solution and only dissolves the shell. This experiment would be done for showing the osmosis process through the cell membrane.
Both dolphins and whales still have their hip (pelvic) bones present. These bones connect and transfer the weight of the trunk to the lower limbs.
Thus, <em>the presence of the pelvic bone may indicate that whales had ancestors that walked on land</em>.
Answer:
Hormones act as first messenger but not as second messengers.
Explanation:
Second messenger act as signaling molecule which are secreted in response to various biological signals generated by first messenger such as hormones,neurotransmitters etc.Second messengers include various bioactive molecules such as cyclic AMP(cAMP),cyclic GMP(cGMP),inositol triphosphate(IP3),diacylglycerol(DAG),calcium ions(Ca2+) etc.
Hormones are extracellular signaling molecules whereas second messengers are intracellular signaling molecules.
I believe is A I’ve learned that in 8th grade I think