Which cells are responsible for development of male reproductive structures

According to piaget, children have acquired the cognitive skill of conservation when they're able to a. understand that six ounces of liquid in a jar and six ounces in an elongated tube are equal. b. understand the viewpoint of other people. c. relate objects around them to their own needs. d. realize that the term heavy describes an object one way and the term big describes it another way. it is not b nor c. did this 2 x wrong..

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

which is an effect of short-term environmental changes? a) adaptation b) speciation c) extinction d) death (5 points)