Answer:
1. D- Within cultures that rely on milk-producing animals, individuals who tolerated lactose had a survival advantage.
2. B- Genetic drift is the random increase or decrease of certain genes in a population; natural selection is not random.
3. A- An interferon activates the body's immune system response to a virus.
4. D- Each persons immune system employs different tactics to get rid of the virus.
5. D- yes, because mutated viruses are able to infect more hosts.
i just did this test, 100% with these answers
The one which is responsible for transmitting an impulse across a synapse to another cell is the neurotransmitters. It allows the transmission of signals from one neuron to the next across synapses.
The correct answer among the choices is letter C.
Answer:
substitution - a base was changed
Explanation:
The nucleotide sequence CTT was changed to the sequence CAT. The T was substituted with an A. This changed the encoded amino acid from Glu to Val.
An insertion is where an additional base is added (e.g. if the sequence changed from CTT to CATT)
A deletion is when a base is lost (e.g. if the sequence changed from CTT to CT)
The human sperm and eggs contain 23 chromosomes. The type of cell division that produces gametes with half the normal chromosome number is called meiosis. It is used to produce cells for repair and asexual reproduction. Gametes do contain different genetic information to each other and to the parent cell.
The B cells are not considered as first line defense structures of the immune’s system
Answer: Option C
<u>Explanation:</u>
Our body is protected internally by nature by many layers of defense. Any microbe or a foreign material that disturbs the body is defended by these barriers.
The first layer of defense required physical and chemical barrier such as the skin, mucous membrane, tears, saliva etc . The second line defense system involves the cells and the tissues that protect the body.
