What do scientists estimate is the approximate age of the planet earth? a) 660 million years b) 3.5 billion years c) 4.6 billion years d) 12.2 billion years

The kind of fertilization found in the majority of aquatic animals is (internal or external) fertilization.

Amylase becomes denatured at a temperature of 80°c. during an experiment to study the effect of varyingtemperature on enzyme activity, amylase’s reactivity with starch was measured at body temperature (37°c), andthen again at an increased temperature of 42°c. how would this increase in temperature affect the experiment

What percentage of light hits earth's surface directly?