20 points more than one answer

which examples of artificial selection are caused by human activity without people even realizing it?

a. an increase of tuskless asian elephants because of ivory poaching
b. growing human organs from pig stem cells because of increased research on stem cell therapy
c. a decrease in rams’ horn size because of hunters’ preference for long-horned rams
d. cows producing milk with more protein because of genetic engineering
e. chickens producing more meat because of selctive breeding

The correct answers are A and C.
The examples D and E also present cases of artificial selection, but the traits, milk production and amount of meat are intentionally selected by the farmers.
On the other hand, in example A, the poachers are not intentionally trying to increase the number of tuskless elephants, but they are accidentally doing so because elephants without tusks are less likely going to be killed by them and have more chances of survival and leaving offspring.
The same thing happens in example C, where the individuals with smaller rams are more likely to survive.

option a is correct i.e.

only sodium ions can pass through the membrane.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

The hawk receives 0.1% energy from the caterpillar although the caterpillar gets eaten by another bird smaller than the hawk first