Answer:
Option B, Observation 2
Explanation:
The four main observation of Darwin’s areas follows –
Observation 1 – Variation occurs in the species with time leading to evolution. Offspring of two parents vary distinctly in traits such as height, color, weight etc. These variations are also affected by the surrounding environment
Observation 2-
Based on observation 1, Darwin concluded that offspring inherit traits from their parents. These traits improve the odds of survival and only genetic traits will be passed. Traits developed in an individual due to environment will not be passed on.
Observation 3 –
Offspring compete among themselves to survive.
Observation 4
The fittest among the competing species for survival will survive and pass on its traits to the next generation.
Since here the Pigeon breeders want to exemplify the looks (a genetic trait) of parents to their offspring, observation 2 applies here
Hence, observation b is correct
Answer:
The correct answer is A acetylcholine binds to a receptor protein on the motor end plate
Explanation:
The neurotransmitter acetylcholine is released by the motor neuron during the transmission of signals across a neuromuscular junction.
The released acetylcholine then diffuses the synaptic cleft and binds to the receptor protein present on the membrane of muscle fibre.
This ultimately result in the influx of sodium ion inside the muscle cell thereby causing depolarization to generate an action potential.
Answer: A) They are the site of protein synthesis.
Explanation:
Ribosomes are small round organelles attached to the endoplasmic reticulum in cells, and serve as site of protein synthesis. This is possible because the transfer RNA assembles amino acids to form polypeptide chains right in the ribosomes.
Thus, ribosomes are site of protein synthesis
Out of the choices given, the conclusion that can be made is that in both cases, societies were brought into contact through trade. The cultural exchanges that went along with that trade enriched those societies. The correct answer is C.