Questions

Corneas are only tissues that don’t have blood vessels. Tissues are the level cellular organization in the human body which lies between cells and a complete organ. Tissues of similar cells group together to form an organ.

There are four types of tissues. They are :

Epithelial,

Connective,

Muscular, and

Nervous tissue.

Syngamy, also known as fertilisation occurs between the male and female gametes. Syngamy may occur either externally, outside the body of organisms or internally, inside the body. Syngamy leads to formation of a specialised cell called diploid zygote.

The error is in third part. The adjective hard has two different adverbs, and they express opposite meanings. The adverb hard is used to modify a verb and means that the action is being done very intensely. The adverb hardly is used to modify a verb and means that the action is not being done very intensely. So there the correct usage will be ‘working hard’.