The correct choice is genetic drift.
genetic drift is known as the variation in alleles number within a population and it mainly happens in small population where chances of losing an alleles are larger. it is common effect observed when significant number in a population die or when there is significant reduction in birth. hence genetic drift results in loss of genetic variation
Magnetic field direction is given by right hand thumb rule.
If we put our thumb in the direction of current then curl of fingers will show the magnetic field direction around the wire.
Now here since current is going into the screen so we will put our thumb into the screen and then the curl of fingers is clockwise around it.
The magnetic field is clockwise.
So this would be the direction of magnetic field
Answer: D.
Explanation: Just took the quiz.
work done is product of force and displacement of point of application of force
so here we have to check the product of force and displacement both
Now we will put the least to maximum work in the following order
1. -A man exerts strenuous effort in pushing a stationary wall
2. -A flea pushes a speck of dirt 1 cm
3. -A farmer pushes a 2 kg wheelbarrow 20 m
4. -A cannon launches a 3 kg cannonball a distance of 200
5. -A 2000 kg car travels 400 m down a road
6. -Space shuttle Atlantis launches from the ground into near-Earth orbit
Explanation:
First, we need to determine the distance traveled by the car in the first 30 minutes,
.
Notice that the unit measurement for speed, in this case, is km/hr. Thus, a unit conversion of from minutes into hours is required before proceeding with the calculation, as shown below

Now, it is known that the car traveled 40 km for the first 30 minutes. Hence, the remaining distance,
, in which the driver reduces the speed to 40km/hr is
.
Subsequently, we would also like to know the time taken for the car to reach its destination, denoted by
.
.
Finally, with all the required values at hand, the average speed of the car for the entire trip is calculated as the ratio of the change in distance over the change in time.

Therefore, the average speed of the car is 50 km/hr.