Heather and Matthew take 60 sec to walk eastward along a straight road to a store 90 m away. What was their speed?

1.5m/s

Explanation:

Using the formula;

Speed (m/s) = distance (metres) ÷ time (seconds)

According to the information provided in this question, Heather and Matthew spend 60seconds to travel a distance of 90 metres. This means that t = 60s, d = 90m

Hence,

Speed = 90/60

Speed = 3/2

Speed = 1.5m/s.

it cools slower in the earth meaning the crystals have more time to form than lava on the surface

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.