1a) 交(出)

jiao (chu)

hand over

head (tou) + crossed legs (symbol)

to sleep together and make love

木

mu

tree

branch, root, trunk

1d) 校

xiao

school

tree (mu) + hand over (jiao)

a wooden structure used for exchanging knowledge

食

shi

eat

?

1b) 饺

jiao

dumpling

eat (shi) + mix/hand over (jiao) 

(with meat and vegetable stuffing)

车 / che

大车 / da che

car

cart

1c) 较

jiao

compare

cart (che) + mix/hand over (jiao)

out of an assortment of cars, they are comparing