Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Sentence1: Endocrine glands include the pituitary, thyroid, parathyroid, adrenal, pineal and thymus glands. 
Sentence2: Some pituitary hormones can control the thyroid gland.
thyroid

Sentence1: Silica sand is primarily mined from sandstone deposits. 
Sentence2: erosion forms silica sand.
Silica

Sentence1: Placental mammals give birth to relatively large and mature infants. 
Sentence2: mammals with wombs give birth to relatively large and mature infants.

birth